Thermally developable imaging system comprising a blocked color-forming agent in association with a hydroxy-substituted aromatic compound for promoting image formation

ABSTRACT

This invention comprises an imaging element comprising an imaging layer having associated therewith a phenolic activating agent in combination with a blocked color-forming agent of Structure I:  
                 
 
     wherein PUG is a photographically useful color-forming agent, LINK 1 and LINK 2 are linking groups; TIME is a timing group; HET is a heterocyclic group, and the other groups are as defined in the specification.

FIELD OF THE INVENTION

[0001] This invention relates to an imaging element containing aspecific type of blocked developer or preformed dye and a phenolic orother hydroxy-substituted aromatic compound for activating theunblocking of the developer or dye.

BACKGROUND OF THE INVENTION

[0002] Conventional color photography employs a light sensitive silverhalide containing films suitable for use in hand-held cameras, whichfilm upon exposure carries a latent image that is revealed aftersuitable processing. Such film has historically been processed bytreating the camera-exposed film with a developing agent that acts toform image. The well known chromogenic dye-forming films employp-aminophenols or p-phenylenediamine developing agents (reducing agents)to form dye images. Traditionally, these reducing agents are typicallypresent in developer solutions that are then brought into reactiveassociation with exposed photographic film at the time of processing.Segregation of the developer and the film element has been necessarybecause the incorporation of developing agent directly into sensitizedphotographic elements frequently leads to desensitization of the silverhalide emulsion and undesirable fog. Considerable effort has thereforebeen directed at trying to produce effective blocked developers, whichcan be introduced in silver halide emulsion elements without deleteriousdesensitization or fog effects and which unblock under conditions ofdevelopment so that the developing agent is free to participate inimage-forming (dye or silver metal forming) reactions.

[0003] U.S. Pat. No. 3,342,599, to Reeves, discloses the use of Schiffbase developer precursors. Schleigh and Faul, in a Research Disclosure(129 (1975) pp. 27-30), described the quaternary blocking of colordeveloping agents and the acetamido blocking of p-phenylenediamines.(All Research Disclosures referenced herein are published by KennethMason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth,Hampshire P010 7DQ, ENGLAND). Subsequently, U.S. Pat. No. 4,157,915, toHamaoka et al., and U.S. Pat. No. 4, 060,418, to Waxman and Mourning,describe the preparation and use of blocked p-phenylenediamines in animage-receiving sheet for color diffusion transfer. Blocked developingagents involving β-elimination reactions during unblocking have beendisclosed in European Patent Application 393523 and kokais 57076453;2131253; and 63123046, the latter specifically in the context ofphotothermographic elements.

[0004] All of these approaches have failed in practical productapplications because of one or more of the following problems:desensitization of sensitized silver halide; unacceptably slowunblocking kinetics; instability of blocked developer yielding increasedfog and/or decreased Dmax after storage, and lack of simple methods ofreleasing the blocked developer.

[0005] U.S. Pat. No. 5,352,561 to Bailey et al. discloses the use ofphenolic compounds (hydroxybenzene derivatives) for forming an improveddye image in an aqueous developable photographic dry dye-diffusiontransfer element. A color coupler forms or releases a heat-transferabledye upon reaction of the coupler with the oxidation product of a primaryamine developing agent. A dye-receiving layer is placed in physicalcontact with the dye-diffusion transfer element and then combinationheated to effect dye-diffusion.

PROBLEM TO BE SOLVED BY THE INVENTION

[0006] There is a continuing need for imaging elements, particularlythermographic and photothermographic imaging elements, that contain adeveloping agent or other color-forming agent that is stable untildevelopment, yet can rapidly and easily develop the imaging element onceprocessing has been initiated by heating the element and/or by applyingto the imaging element a small volume of processing solution, such as asolution of a base or acid or pure water, in the presence of heat. Forrapid access capability of photothermographic film, the developing agentmust be in the form of an incorporated blocked developer that is highlyreactive so that a great amount of the developing agent can be producedin a short period of time during processing. Such high reactivity mustnot lead to difficulty in the production and handling of thesematerials. In general, increased image density formation at lower onsettemperatures is desirable, to minimize undesirable effects that tend tooccur at higher onset temperatures. The existence of such developerchemistry will allow for very rapidly processed films that can beprocessed simply and efficiently, proving one-stop photoprocessing oreven photoprocessing kiosks.

SUMMARY OF THE INVENTION

[0007] This invention is directed to a photothermographic elementcomprising a combination of (1) a type of blocked developer or othercolor-forming agent in which the unblocking by a 1,2-eliminationreaction is activated by an N-containing heterocyclic moiety, and (2) ahydroxy-substituted aromatic compound, referred to herein as a “phenoliccompound”, also referred to herein as an “activating agent” thatpromotes the unblocking of the blocked developing agent or othercolor-forming agent, thereby facilitating image formation. The twocomponents are in “association,” by which is meant that the activatingagent must be sufficiently near to the color-forming agent toparticipate in the unblocking reaction, even though the activating agentis not itself chemically changed in the reaction. It has been found thata blocked color-forming agent in combination with a phenolic compound,in accordance with the present invention, can significantly acceleratethe release of the color-forming agent upon heat processing. The use ofthe claimed combination in a photographic element can, therefore,provide rapid access capability for a photothermographic element atrelatively lower temperatures. Solution measurement of the deblockingreaction suggests very slow reaction without phenol catalysis andsignificant acceleration by phenol catalysis. By bringing the blockedcolor-forming agent in contact with the phenolic compound only duringprocessing, high stability at storage temperature and reactivity atprocessing temperature can be achieved. Another result of theinteraction between the blocked color-forming agent and the phenoliccompound during development is that image formation is improved,including an increase in image-density formation.

[0008] The invention additionally relates to a method of image formationhaving the steps of thermally developing an imagewise exposedphotothermographic element having a heteroaromatic moiety that enablesrelease of a developer on thermal activation to form a developed image,scanning said developed image to form a first electronic imagerepresentation from said developed image, digitizing said firstelectronic record to form a digital image, modifying said digital imageto form a second electronic image representation, and storing,transmitting, printing or displaying said second electronic imagerepresentation.

[0009] The invention also relates to thermographic imaging elements andmethods of image formation involving release of a developer or preformeddye on thermal activation.

DETAILED DESCRIPTION OF THE INVENTION

[0010] As mentioned above, this invention relates to an imaging elementcontaining specific blocked developers or other color-forming agent anda phenolic activating agent. The blocked color-forming agent has aheteroaromatic moiety that enables release of a photographically usefulgroup on thermal activation. In one embodiment, the general structurefor the blocked developer is shown below:

[0011] wherein LINK1 and LINK2 are linking groups, TIME is a timinggroup; HET=heterocyclic group, T_((t)) and R₁₂ are substituents, 1 and nare independently 0 or 1; and m is 0, 1, or 2. In thermal imagingsystems, when the blocked PUG (“photographically useful group”) is adeveloper, the blocked compound releases the developer to give usefulquantities of chromogenic development when elements containing them areheated.

[0012] The general structures for the hydroxy-substituted aromaticcompound is Ar—(OH)_(q), wherein q≧1, preferably 1 to 4, more preferably1, and Ar is a substituted or unsubstituted aromatic group. Some of thephenolic compounds useful in the present invention are also useful asthermal solvents or melt formers in photothermographic systems. Seecommonly assigned, copending U.S. Ser. No. 60/211,452, herebyincorporated by reference in its entirety. Thus, the phenolic compoundsof the present invention can have a dual function, both promotingunblocking as well as providing a solvent for reactants during thermaldevelopment. However, imaging elements according to the presentinvention can comprise conventional melt formers or thermal solvents,including, for example, benzamide, dimethylurea, and many other groupsof compounds which provide improved image formation and discrimination.It has been found, however, that the use of conventional benzamide ordimethylurea as a thermal solvent does not significantly improve theimage formation characteristics of the film with blocked developersemployed in the present invention.

[0013] As mentioned above, the phenolic compounds according to thepresent invention not only contribute to high dye density formation, butalso can lower the processing temperature, lending more flexibility toutilizing these blocked compounds in practice.

[0014] In one embodiment, thermal activation preferably occurs attemperatures between about 100 and 160° C., preferably to about 140° C.or below, more preferably to about 130° C. or below. In anotherembodiment, thermal activation preferably occurs at temperatures betweenabout 20 and 100° C. in the presence of added acid, base or water.

[0015] The invention, therefore, relates to a light sensitivephotothermographic element comprising a support and comprising theblocked developer having a heteroaromatic moiety in combination with aphenolic activator that enables release of the developer on thermalactivation.

[0016] The linking groups LINK 1 and LINK 2 are independently selectedfrom of Structure II:

[0017] wherein

[0018] X represents carbon or sulfur;

[0019] Y represents oxygen, sulfur or N—R₁, where R₁ is substituted orunsubstituted alkyl or substituted or unsubstituted aryl;

[0020] pis 1 or 2;

[0021] Z represents carbon, oxygen or sulfur;

[0022] r is 0 or 1;

[0023] with the proviso that when X is carbon, both p and r are 1, whenX is sulfur, Y is oxygen, p is 2 and r is 0;

[0024] # denotes the bond to PUG (for LINK 1) or TIME (for LINK 2):

[0025] $ denotes the bond to TIME (for LINK 1) or T_((t)) substitutedcarbon (for LINK 2).

[0026] In structure I, the PUG is a color-forming agent that can be, forexample, a photographic dye or a photographic reagent. A photographicreagent herein is a moiety that upon release further reacts withcomponents in the photographic element. Such photographically usefulgroups include, for example, couplers (such as, image dye-formingcouplers, development inhibitor releasing couplers, competing couplers,polymeric couplers and other forms of couplers), development inhibitors,inhibitor releasing developers, dyes and dye precursors, developingagents (such as competing developing agents, dye-forming developingagents, developing agent precursors, and silver halide developingagents). By the term “color-forming agent” is meant that the PUG isinvolved in the formation of image color or dye density in an imaginglayer, either positively increasing color formation or negativelydecreasing or limiting color formation.

[0027] The PUG can be present in the blocked compound as a preformedspecies or as a precursor. For example, a preformed developmentinhibitor may be bonded to the blocking group or the developmentinhibitor may be attached to a timing group that is released at aparticular time and location in the photographic material. The PUG maybe, for example, a preformed dye or a compound that forms a dye afterrelease from the blocking group.

[0028] In preferred embodiments of the invention the PUG is a developingagent. The developing agent can be a color developing agent, ablack-and-white developing agent or a cross-oxidized developing agent.They include aminophenols, phenylenediamines, hydroquinones,pyrazolidinones, and hydrazines. Illustrative developing agents aredescribed in U.S. Pat. Nos. 2,193,015, 2,108,243, 2,592,364, 3,656,950,3,658,525, 2,751,297, 2,289,367, 2,772,282, 2,743,279, 2,753,256, and2,304,953, the entire disclosures of which are incorporated herein byreference.

[0029] Illustrative PUG groups that are useful as developers are:

[0030] wherein

[0031] R₂₀ is hydrogen, halogen, alkyl or alkoxy;

[0032] R₂₁ is a hydrogen or alkyl;

[0033] R₂₂ is hydrogen, alkyl, alkoxy or alkenedioxy; and

[0034] R₂₃, R₂₄, R₂₅ R₂₆ and R₂₇ are hydrogen alkyl, hydroxyalkyl orsulfoalkyl.

[0035] As mentioned above, in a preferred embodiment of the invention,LINK 1 or LINK 2 are of structure II:

[0036] wherein

[0037] X represents carbon or sulfur;

[0038] Y represents oxygen, sulfur of N—R₁, where R₁ is substituted orunsubstituted alkyl or substituted or unsubstituted aryl;

[0039] p is 1 or 2;

[0040] Z represents carbon, oxygen or sulfur;

[0041] r is 0 or 1;

[0042] with the proviso that when X is carbon, both p and r are 1, whenX is sulfur, Y is oxygen, p is 2 and r is 0;

[0043] # denotes the bond to PUG (for LINK 1) or TIME (for LINK 2):

[0044] $ denotes the bond to TIME (for LINK 1) or T_((t)) substitutedcarbon (for LINK 2).

[0045] Illustrative linking groups include, for example,

[0046] TIME is a timing group. Such groups are well-known in the artsuch as (1) groups utilizing an aromatic nucleophilic substitutionreaction as disclosed in U.S. Pat. No. 5,262,291; (2) groups utilizingthe cleavage reaction of a hemiacetal (U.S. Pat. No. 4,146,396, JapaneseApplications 60-249148; 60-249149); (3) groups utilizing an electrontransfer reaction along a conjugated system (U.S. Pat. Nos. 4,409,323;4,421,845; Japanese Applications 57-188035; 58-98728; 58-209736;58-209738); and (4) groups using an intramolecular nucleophilicsubstitution reaction (U.S. Pat. No. 4,248,962).

[0047] Illustrative timing groups are illustrated by formulae T-1through T-4.

[0048] wherein:

[0049] Nu is a nucleophilic group;

[0050] E is an electrophilic group comprising one or more carbo- orhetero- aromatic rings, containing an electron deficient carbon atom;

[0051] LINK 3 is a linking group that provides 1 to 5 atoms in thedirect path between the nucleopnilic site of Nu and the electrondeficient carbon atom in E; and

[0052] a is 0 or 1.

[0053] Such timing groups include, for example:

[0054] These timing groups are described more fully in U.S. Pat. No.5,262,291, incorporated herein by reference.

[0055] wherein

[0056] V represents an oxygen atom, a sulfur atom, or an

[0057] group;

[0058] R₁₃ and R₁₄ each represents a hydrogen atom or a substituentgroup;

[0059] R₁₅ represents a substituent group; and b represents 1 or 2.

[0060] Typical examples of R₁₃ and R₁₄, when they represent substituentgroups, and R₁₅ include

[0061] where, R₁₆ represents an aliphatic or aromatic hydrocarbonresidue, or a heterocyclic group; and R₁₇ represents a hydrogen atom, analiphatic or aromatic hydrocarbon residue, or a heterocyclic group, R₁₃,R₁₄ and R₁₅ each may represent a divalent group, and any two of themcombine with each other to complete a ring structure. Specific examplesof the group represented by formula (T-2) are illustrated below.

[0062] wherein Nu 1 represents a nucleophilic group, and an oxygen orsulfur atom can be given as an example of nucleophilic species; E1represents an electrophilic group being a group which is subjected tonucleophilic attack by Nu 1; and LINK 4 represents a linking group whichenables Nu 1 and E1 to have a steric arrangement such that anintramnolecular nucleophilic substitution reaction can occur. Specificexamples of the group represented by formula (T-3) are illustratedbelow.

[0063] wherein V, R₁₃, R₁₄ and b all have the same meaning as in formula(T-2), respectively. In addition, R₁₃ and R₁₄ may be joined together toform a benzene ring or a heterocyclic ring, or V may be joined with R₁₃or R₁₄ to form a benzene or heterocyclic ring. Z₁ and Z₂ eachindependently represents a carbon atom or a nitrogen atom, and x and yeach represents 0 or 1.

[0064] Specific examples of the timing group (T-4) are illustratedbelow.

[0065] A preferred embodiment of the invention comprises an imagingelement comprising an imaging layer having associated therewith acompound of Structure I:

[0066] wherein

[0067] PUG is a color-forming agent;

[0068] TIME is a timing group as described below;

[0069] T represents t independently selected substituted orunsubstituted alkyl (preferably containing 1 to 6 carbon atoms) or arylgroups (preferably phenyl or naphthyl), t is 0, 1, or 2 and if t is 2,the T groups can form a ring;

[0070] HET is a heterocyclic group that optionally can form a ring witha T group;

[0071] R₁₂ is hydrogen, substituted or unsubstituted alkyl orsubstituted or unsubstituted aryl, or R₁₂ can form a ring with a T groupor with HET;

[0072] l is 0 or 1;

[0073] mis 0, 1, or2; and

[0074] n is 0 or 1.

[0075] HBET is preferably a substituted or unsubstituted 4 or 7-memberedring, preferably a 5 or 6-membered ring, containing one or moreheteroatoms, such as N, O, S or Se. Preferably, the heterocyclic (HET)group of Structure I comprises, for example, a substituted orunsubstituted benzimidazolyl, benzothiazolyl, benzoxazolyl,benzothiophenyl, benzofuryl, furyl, imidazolyl, indazolyl, indolyl,isoquinolyl, isothiazolyl, isoxazolyl, oxazolyl, picolinyl, purinyl,pyranyl, pyrazinyl, pyrazolyl, pyridyl, pyrimidinyl, pyrrolyl,quinaldinyl, quinazolinyl, quinolyl, quinoxalinyl, tetrazolyl,thiadiazolyl, thiatriazolyl, thiazolyl, thiophenyl, and triazolyl group.Particularly preferred are: 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl,2-benzothiazolyl, 2-oxazolyl, 2-benzoxazolyl, 2-pyridyl, 2-quinolinyl,1-isoquinolinyl, 2-pyrrolyl, 2-indolyl, 2-thiophenyl, 2-benzothiophenyl,2-furyl, 2-benzofuryl, 2-, 4-, or 5-pyrimidinyl, 2-pyrazinyl, 3-,4-, or5-pyrazolyl, 3-indazolyl, 2-(1,3,4-triazolyl), 4-or 5-(1,2,3-triazolyl),5-(1,2,3,4-tetrazolyl). The heterocyclic group may be furthersubstituted. Preferred substituents are alkyl and alkoxy groupscontaining 1 to 6 carbon atoms.

[0076] Particularly preferred photographically useful compounds areblocked developers of Structure III:

[0077] wherein:

[0078] HET is a heterocyclic group;

[0079] W is OH or NR₂R₃, and R₂ and R₃ are independently hydrogen or asubstituted or unsubstituted alkyl group or R₂ and R₃ are connected toform a ring;

[0080] R₅, R₆, R₇, and R₈ are independently hydrogen, halogen, hydroxy,amino, alkoxy, carbonamido, sulfonamido, alkylsulfonamido or alkyl, orR₅ can connect with R₃ or R₆ and/or R₈ can connect to R₄ or R₇ to form aring;

[0081] R₉, R₁₀ and R₁₁ are independently hydrogen, alkyl, aryl,heteroaromatic or alkoxy groups, or any two of R₉, R₁₀, R₁₁ and HET canbe connected to form a ring.

[0082] When reference in this application is made to a particularmoiety, or group, this means that the moiety may itself be unsubstitutedor substituted with one or more substituents (up to the maximum possiblenumber). For example, “alkyl” or “alkyl group” refers to a substitutedor unsubstituted alkyl, while “aryl group” refers to a substituted orunsubstituted benzene (with up to five substituents) or higher aromaticsystems. Generally, unless otherwise specifically stated, substituentgroups usable on molecules herein include any groups, whethersubstituted or unsubstituted, which do not destroy properties necessaryfor the photographic utility. Examples of substituents on any of thementioned groups can include known substituents, such as: halogen, forexample, chloro, fluoro, bromo, iodo; alkoxy, particularly those “loweralkyl” (that is, with 1 to 6 carbon atoms), for example, methoxy,ethoxy; substituted or unsubstituted alkyl, particularly lower alkyl(for example, methyl, trifluoromethyl); thioalkyl (for example,methylthio or ethylthio), particularly either of those with 1 to 6carbon atoms; substituted and unsubstituted aryl, particularly thosehaving from 6 to 20 carbon atoms (for example, phenyl); and substitutedor unsubstituted heteroaryl, particularly those having a 5 or 6-memberedring containing 1 to 3 heteroatoms selected from N, O, or S (forexample, pyridyl, thienyl, furyl, pyrrolyl); acid or acid salt groupssuch as any of those described below; and others known in the art. Alkylsubstituents may specifically include “lower alkyl” (that is, having 1-6carbon atoms), for example, methyl, ethyl, and the like. Further, withregard to any alkyl group or alkylene group, it will be understood thatthese can be branched, unbranched or cyclic. By the term “ring” is meantsaturated, unsaturated or aromatic rings, preferably having 4 to 10carbon atoms in the ring.

[0083] The following are representative examples of compounds ofStructure III:

[0084] The blocked developer is preferably incorporated in one or moreof the imaging layers of the imaging element. The amount of blockeddeveloper used is preferably 0.01 to 5 g/m², more preferably 0.1 to 2g/m² and most preferably 0.3 to 2 g/m² in each layer to which it isadded. These may be color forming or non-color forming layers of theelement. The blocked developer can be contained in a separate elementthat is contacted to the photographic element during processing.

[0085] The general structures for the phenolic promoter (IV) is shownbelow:

Ar—(OH)_(q)   IV

[0086] wherein q≧1 and Ar is a substituted or unsubstituted aromaticgroup, preferably a phenyl ring. Preferably q is 1 or 2. Representativeexamples of Phenolic compounds according to the present invention are asfollows: ID Structure A-1

A-2

A-3

A-4

A-5

A-6

A-7

A-8

A-9

A-10

A-11

A-12

A-13

A-14

A-15

A-16

A-17

A-18

A-19

A-22

A-23

[0087] The melting points of the phenolic compounds above are listedbelow: ID Melting point, ° C. A-1 134 A-2 191 A-3 159 A-4 208 A-5 248A-6 248 A-7  NA* A-8 159 A-9 NA A-10 NA A-11 117 A-12 160 A-13 102 A-14158 A-15 193 A-16 >325 A-17 224 A-18 93 A-19 NA A-22 120-123 A-23128-133

[0088] Preferably, the activating compounds employed in our inventionhave a phenolic—OH group that is weakly acidic characterized by a lowpK_(a) value. By “phenolic” is meant that the —OH group is a substituenton an aromatic ring. Phenolic compounds in which there is orthosubstitution adjacent the hydroxy group is also preferred, particularlywhen it contributes to the acidity of the hydroxy group. Preferably, thesubstituents are electron withdrawing on the aromatic ring. Preferably,the pKa is less than 10, more preferably 6 to 9.5, most preferably about8-9.

[0089] In one particular embodiment, an activating agent is includingaccording to the following Structure V:

[0090] wherein B is selected from the group consisting of —C(═O)NHR³,—NHC(═O)R³, —NHSO₂R³, —C(═O)R³, —C(═O)OR³, —OR³, —SO₂NHR³, and -S0₂R³;where R³ is hydrogen or substituted or unsubstituted alkyl group and Rand n is as defined above; and m is 0 to 4. Preferably, the substituentR is independently selected from a substituted or unsubstituted alkyl,ether, cycloalkyl, aryl, alkylaryl, hydroxy, carboxylic acid, nitro,halogen, heteroaromatic, or two R substituent forms an aromatic oraliphatic or unsaturated ring; n is 0 to 4; and wherein m+n is 1 to 5.

[0091] Substituents on R or B can include any substituent that does notadversely affect the activating agent fuinction, for example, a halogen.The substituents R or B can also comprise another phenolic group.

[0092] In one embodiment, the phenolic compound preferably has a meltingpoint of at least 80° C., preferably 80° C. to 300° C., more preferablybetween 100 and 250° C. Preferably, m+n is 1 or 2. In one embodiment,when m is 0, there is a second phenolic group on an R substituent. It isnoted that two bulky alkyl (for example, tertiary C₄) substituents orthoto the phenolic group may reduce the effectiveness of the activatingagent.

[0093] Preferably, the phenolic compound is represented by the followingstructure:

[0094] wherein LINK can be —C(═O)NH—, —NHC(═O)—, —NHSO₂—, —C(═O)—,—C(═O)O—, —O—, —SO₂NH—, and —SO₂—, wherein R and n are as defined above,and p is 0 to 4. Preferably R is independently selected from substitutedor unsubstituted alkyl, preferably a C1 to C10 alkyl group. In oneembodiment n and p are independently 0 or 1. In another embodiment,n+p=1.

[0095] Typically, the activating agent is present in an imaging layer ofthe photothermographic element in the amount of 0.01 times to 0.5 timesthe amount by weight of coated gelatin per square meter.

[0096] As will be appreciated by the skilled artisan, many phenolicactivating agents according to the present invention may be made bysimple reactions between appropriate intermediates, for example,activating agent A-2 can be prepared by treating 4-methyl salicylic acidwith aniline. Methods for synthesizing phenolic compounds according tothe present invention can be found in a variety of patent or literaturereferences. For example, synthetic methods for making hydroxynaphthoicacid derivatives are disclosed by Ishida, Katsuhiko; Nojima, Masaharu;Yamamoto, Tamotsu; and Okamoto, Tosaku in Japanese Patent JP 61041595 A2(1986) and JP 04003759 (1992) and Japanese Kokai JP 84-163718 (1984).Synthetic methods for making N-Substituted salicylamides are disclosedby Ciampa, Giuseppe and Grieco, Ciro., Univ. Naples, Rend. Accad. Sci.Fis. Mat. (Soc. Naz. Sci., Lett. Arti Napoli) (1966), 33(Dec.), 396-403.

[0097] Methods for the preparation of the anilides of phenolcarboxylicacids are disclosed by Burmistrov, S. I. and Limarenko, L. I., inU.S.S.R. Patent SU 189869 (1966) and Application SU 19660128. Forexample, anilides were prepared by treating phenolates withphenylurethane in a high-boiling organic solvent, e.g., cumene or thediethylbenzene fraction from the production of PhEt, with heating. Sucha method can be used in the synthesis of activating agent A-2 above.

[0098] A Friedel-Crafts reaction, involving the synthesis ofsalicylanilides via ortho-aminocarbonylation of phenols with phenylisocyanate can be used in the synthesis of activating agents A-11 andA-12 above. Such a method is reported by Balduzzi, Gianluigi; Bigi,Franca; Casiraghi, Giovanni; Casnati, and Giuseppe; Sartori, Giovanni,Ist. Chim. Org., Univ. Parma, Parma, Italy, in the journal Synthesis(1982), (10), 879-81. For example, the reaction of“a” below with PhNCOin the presence of AlCl₃ in xylene gave “b,” where R, R¹, R², R³=H, H,H, H or Me, H, H, H or H, H, Me, H or H, MeO, H, H or H, H, MeO, H or H,Me, H, Me, or H, OH, H, H or H, H, R²R³=(CH:CH)₂.

[0099] Methods of preparing bisphenol compounds are disclosed inJapanese Patent JP 56108759 A2 (1981) and Application: JP 80-8234(1980). For example, bisphenol disulfonamides were prepared frombis(benzotriazolyl sulfonates). Thus, in one case, bis(1-benzotriazolyl)diphenyl ether-4,4′-disulfonate was added to 4-aminophenol in pyridinewith ice cooling and the mixture stirred 24 hours at room temperature togive N,N′-bis(p-hydroxyphenyl)diphenyl ether-4,4′-disulfonamide. Suchmethods can be used, for example, to make activating agent A-15 aboveand the like.

[0100] After image-wise exposure of the imaging element, the blockeddeveloper is activated during processing of the imaging element by thepresence of acid or base in the processing solution, by heating theimaging element during processing of the imaging element, and/or byplacing the imaging element in contact with a separate element, such asa laminate sheet, during processing. The laminate sheet optionallycontains additional processing chemicals such as those disclosed inSections XIX and XX of Research Disclosure, September 1996, Number 389,Item 38957 (hereafter referred to as (“Research Disclosure I”). Allsections referred to herein are sections of Research Disclosure I,unless otherwise indicated. Research Disclosure I, Such chemicalsinclude, for example, sulfites, hydroxyl amine, hydroxamic acids and thelike, antifoggants, such as alkali metal halides, nitrogen containingheterocyclic compounds, and the like, sequestering agents such as anorganic acids, and other additives such as buffering agents, sulfonatedpolystyrene, stain reducing agents, biocides, desilvering agents,stabilizers and the like.

[0101] The blocked compounds may be used in any form of photographicsystem. A typical color negative film construction useful in thepractice of the invention is illustrated by the following element,SCN-1: Element SCN-1 SOC Surface Overcoat BU Blue Recording Layer UnitIL1 First Interlayer GU Green Recording Layer Unit IL2 Second InterlayerRU Red Recording Layer Unit AHU Antihalation Layer Unit S Support SOCSurface Overcoat

[0102] The support S can be either reflective or transparent, which isusually preferred. When reflective, the support is white and can takethe form of any conventional support currently employed in color printelements. When the support is transparent, it can be colorless or tintedand can take the form of any conventional support currently employed incolor negative elements—e.g., a colorless or tinted transparent filmsupport. Details of support construction are well understood in the art.Examples of useful supports are poly(vinylacetal) film, polystyrenefilm, poly(ethyleneterephthalate) film, poly(ethylene naphthalate) film,polycarbonate film, and related films and resinous materials, as well aspaper, cloth, glass, metal, and other supports that withstand theanticipated processing conditions. The element can contain additionallayers, such as filter layers, interlayers, overcoat layers, subbinglayers, antihalation layers and the like. Transparent and reflectivesupport constructions, including subbing layers to enhance adhesion, aredisclosed in Section XV of Research Disclosure I.

[0103] Photographic elements of the present invention may also usefullyinclude a magnetic recording material as described in ResearchDisclosure, Item 34390, November 1992, or a transparent magneticrecording layer such as a layer containing magnetic particles on theunderside of a transparent support as in U.S. Pat. No. 4,279,945, andU.S. Pat. No. 4,302,523.

[0104] Each of blue, green and red recording layer units BU, GU and RUare formed of one or more hydrophilic colloid layers and contain atleast one radiation-sensitive silver halide emulsion and coupler,including at least one dye image-forming coupler. It is preferred thatthe green, and red recording units are subdivided into at least tworecording layer sub-units to provide increased recording latitude andreduced image granularity. In the simplest contemplated constructioneach of the layer units or layer sub-units consists of a singlehydrophilic colloid layer containing emulsion and coupler. When couplerpresent in a layer unit or layer sub-unit is coated in a hydrophiliccolloid layer other than an emulsion containing layer, the couplercontaining hydrophilic colloid layer is positioned to receive oxidizedcolor developing agent from the emulsion during development. Usually thecoupler containing layer is the next adjacent hydrophilic colloid layerto the emulsion containing layer.

[0105] In order to ensure excellent image sharpness, and to facilitatemanufacture and use in cameras, all of the sensitized layers arepreferably positioned on a common face of the support. When in spoolform, the element will be spooled such that when unspooled in a camera,exposing light strikes all of the sensitized layers before striking theface of the support carrying these layers. Further, to ensure excellentsharpness of images exposed onto the element, the total thickness of thelayer units above the support should be controlled. Generally, the totalthickness of the sensitized layers, interlayers and protective layers onthe exposure face of the support are less than 35 μm.

[0106] Any convenient selection from among conventionalradiation-sensitive silver halide emulsions can be incorporated withinthe layer units and used to provide the spectral absorptances of theinvention. Most commonly high bromide emulsions containing a minoramount of iodide are employed. To realize higher rates of processing,high chloride emulsions can be employed. Radiation-sensitive silverchloride, silver bromide, silver iodobromide, silver iodochloride,silver chlorobromide, silver bromochloride, silver iodochlorobromide andsilver iodobromochloride grains are all contemplated. The grains can beeither regular or irregular (e.g., tabular). Tabular grain emulsions,those in which tabular grains account for at least 50 (preferably atleast 70 and optimally at least 90) percent of total grain projectedarea are particularly advantageous for increasing speed in relation togranularity. To be considered tabular a grain requires two majorparallel faces with a ratio of its equivalent circular diameter (ECD) toits thickness of at least 2. Specifically preferred tabular grainemulsions are those having a tabular grain average aspect ratio of atleast 5 and, optimally, greater than 8. Preferred mean tabular grainthicknesses are less than 0.3 μm (most preferably less than 0.2 μm).Ultrathin tabular grain emulsions, those with mean tabular grainthicknesses of less than 0.07 μm, are specifically contemplated. Thegrains preferably form surface latent images so that they producenegative images when processed in a surface developer in color negativefilm forms of the invention.

[0107] Illustrations of conventional radiation-sensitive silver halideemulsions are provided by Research Disclosure I, cited above, I.Emulsion grains and their preparation. Chemical sensitization of theemulsions, which can take any conventional form, is illustrated insection IV. Chemical sensitization. Compounds useful as chemicalsensitizers, include, for example, active gelatin, sulfur, selenium,tellurium, gold, platinum, palladium, iridium, osmium, rhenium,phosphorous, or combinations thereof. Chemical sensitization isgenerally carried out at pAg levels of from 5 to 10, pH levels of from 4to 8, and temperatures of from 30 to 80° C. Spectral sensitization andsensitizing dyes, which can take any conventional form, are illustratedby section V. Spectral sensitization and desensitization. The dye may beadded to an emulsion of the silver halide grains and a hydrophiliccolloid at any time prior to (e.g., during or after chemicalsensitization) or simultaneous with the coating of the emulsion on aphotographic element. The dyes may, for example, be added as a solutionin water or an alcohol or as a dispersion of solid particles. Theemulsion layers also typically include one or more antifoggants orstabilizers, which can take any conventional form, as illustrated bysection VII. Antifoggants and stabilizers.

[0108] The silver halide grains to be used in the invention may beprepared according to methods known in the art, such as those describedin Research Disclosure I, cited above, and James, The Theory of thePhotographic Process. These include methods such as ammoniacal emulsionmaking, neutral or acidic emulsion making, and others known in the art.These methods generally involve mixing a water soluble silver salt witha water soluble halide salt in the presence of a protective colloid, andcontrolling the temperature, pAg, pH values, etc, at suitable valuesduring formation of the silver halide by precipitation.

[0109] In the course of grain precipitation one or more dopants (grainocclusions other than silver and halide) can be introduced to modifygrain properties. For example, any of the various conventional dopantsdisclosed in Research Disclosure I, Section I. Emulsion grains and theirpreparation, sub-section G. Grain modifying conditions and adjustments,paragraphs (3), (4) and (5), can be present in the emulsions of theinvention. In addition it is specifically contemplated to dope thegrains with transition metal hexacoordination complexes containing oneor more organic ligands, as taught by Olm et al U.S. Pat. No. 5,360,712,the disclosure of which is here incorporated by reference.

[0110] It is specifically contemplated to incorporate in the facecentered cubic crystal lattice of the grains a dopant capable ofincreasing imaging speed by forming a shallow electron trap (hereinafteralso referred to as a SET) as discussed in Research Disclosure Item36736 published November 1994, here incorporated by reference.

[0111] The SET dopants are effective at any location within the grains.Generally better results are obtained when the SET dopant isincorporated in the exterior 50 percent of the grain, based on silver.An optimum grain region for SET incorporation is that formed by silverranging from 50 to 85 percent of total silver forming the grains. TheSET can be introduced all at once or run into the reaction vessel over aperiod of time while grain precipitation is continuing. Generally SETforming dopants are contemplated to be incorporated in concentrations ofat least 1×10⁻⁷ mole per silver mole up to their solubility limit,typically up to about 5×10⁻⁴ mole per silver mole.

[0112] SET dopants are known to be effective to reduce reciprocityfailure. In particular the use of iridium hexacoordination complexes orIr⁺⁴ complexes as SET dopants is advantageous.

[0113] Iridium dopants that are ineffective to provide shallow electrontraps (non-SET dopants) can also be incorporated into the grains of thesilver halide grain emulsions to reduce reciprocity failure.

[0114] To be effective for reciprocity improvement the Ir can be presentat any location within the grain structure. A preferred location withinthe grain structure for Ir dopants to produce reciprocity improvement isin the region of the grains formed after the first 60 percent and beforethe final 1 percent (most preferably before the final 3 percent) oftotal silver forming the grains has been precipitated. The dopant can beintroduced all at once or run into the reaction vessel over a period oftime while grain precipitation is continuing. Generally reciprocityimproving non-SET Ir dopants are contemplated to be incorporated attheir lowest effective concentrations.

[0115] The contrast of the photographic element can be further increasedby doping the grains with a hexacoordination complex containing anitrosyl or thionitrosyl ligand (NZ dopants) as disclosed in McDugle etal U.S. Pat. No. 4,933,272, the disclosure of which is here incorporatedby reference.

[0116] The contrast increasing dopants can be incorporated in the grainstructure at any convenient location. However, if the NZ dopant ispresent at the surface of the grain, it can reduce the sensitivity ofthe grains. It is therefore preferred that the NZ dopants be located inthe grain so that they are separated from the grain surface by at least1 percent (most preferably at least 3 percent) of the total silverprecipitated in forming the silver iodochloride grains. Preferredcontrast enhancing concentrations of the NZ dopants range from 1×10⁻¹¹to 4×10⁻⁸ mole per silver mole, with specifically preferredconcentrations being in the range from 10⁻¹⁰ to 10⁻⁸ mole per silvermole.

[0117] Although generally preferred concentration ranges for the variousSET, non-SET Ir and NZ dopants have been set out above, it is recognizedthat specific optimum concentration ranges within these general rangescan be identified for specific applications by routine testing. It isspecifically contemplated to employ the SET, non-SET Ir and NZ dopantssingly or in combination. For example, grains containing a combinationof an SET dopant and a non-SET Ir dopant are specifically contemplated.Similarly SET and NZ dopants can be employed in combination. Also NZ andIr dopants that are not SET dopants can be employed in combination.Finally, the combination of a non-SET Ir dopant with a SET dopant and anNZ dopant. For this latter three-way combination of dopants it isgenerally most convenient in terms of precipitation to incorporate theNZ dopant first, followed by the SET dopant, with the non-SET Ir dopantincorporated last.

[0118] The photographic elements of the present invention, as istypical, provide the silver halide in the form of an emulsion.Photographic emulsions generally include a vehicle for coating theemulsion as a layer of a photographic element. Useful vehicles includeboth naturally occurring substances such as proteins, proteinderivatives, cellulose derivatives (e.g., cellulose esters), gelatin(e.g., alkali-treated gelatin such as cattle bone or hide gelatin, oracid treated gelatin such as pigskin gelatin), deionized gelatin,gelatin derivatives (e.g., acetylated gelatin, phthalated gelatin, andthe like), and others as described in Research Disclosure, I. Alsouseful as vehicles or vehicle extenders are hydrophilic water-permeablecolloids. These include synthetic polymeric peptizers, carriers, and/orbinders such as poly(vinyl alcohol), poly(vinyl lactams), acrylamidepolymers, polyvinyl acetals, polymers of alkyl and sulfoalkyl acrylatesand methacrylates, hydrolyzed polyvinyl acetates, polyamides, polyvinylpyridine, methacrylamide copolymers. The vehicle can be present in theemulsion in any amount useful in photographic emulsions. The emulsioncan also include any of the addenda known to be useful in photographicemulsions.

[0119] While any useful quantity of light sensitive silver, as silverhalide, can be employed in the elements useful in this invention, it ispreferred that the total quantity be less than 10 g/m² of silver. Silverquantities of less than 7 g/m² are preferred, and silver quantities ofless than 5 g/m² are even more preferred. The lower quantities of silverimprove the optics of the elements, thus enabling the production ofsharper pictures using the elements. These lower quantities of silverare additionally important in that they enable rapid development anddesilvering of the elements. Conversely, a silver coating coverage of atleast 1.5 g of coated silver per m² of support surface area in theelement is necessary to realize an exposure latitude of at least 2.7 logE while maintaining an adequately low graininess position for picturesintended to be enlarged.

[0120] BU contains at least one yellow dye image-forming coupler, GUcontains at least one magenta dye image-forming coupler, and RU containsat least one cyan dye image-forming coupler. Any convenient combinationof conventional dye image-forming couplers can be employed. Conventionaldye image-forming couplers are illustrated by Research Disclosure I,cited above, X. Dye image formers and modifiers, B. Image-dye-formingcouplers. The photographic elements may further contain otherimage-modifying compounds such as “Development Inhibitor-Releasing”compounds (DIR's). Useful additional DIR's for elements of the presentinvention, are known in the art and examples are described in U.S. Pat.Nos. 3,137,578; 3,148,022; 3,148,062; 3,227,554; 3,384,657; 3,379,529;3,615,506; 3,617,291; 3,620,746; 3,701,783; 3,733,201; 4,049,455;4,095,984; 4,126,459; 4,149,886; 4,150,228; 4,211,562; 4,248,962;4,259,437; 4,362,878; 4,409,323; 4,477,563; 4,782,012; 4,962,018;4,500,634; 4,579,816; 4,607,004; 4,618,571; 4,678,739; 4,746,600;4,746,601; 4,791,049; 4,857,447; 4,865,959; 4,880,342; 4,886,736;4,937,179; 4,946,767; 4,948,716; 4,952,485; 4,956,269; 4,959,299;4,966,835; 4,985,336 as well as in patent publications GB 1,560,240; GB2,007,662; GB 2,032,914; GB 2,099,167; DE 2,842,063, DE 2,937,127; DE3,636,824; DE 3,644,416 as well as the following European PatentPublications: 272,573; 335,319; 336,411; 346,899; 362,870; 365,252;365,346; 373,382; 376,212; 377,463; 378,236; 384,670; 396,486; 401,612;401,613.

[0121] DIR compounds are also disclosed in“Developer-Inhibitor-Releasing (DIR) Couplers for Color Photography,” C.R. Barr, J. R. Thirtle and P. W. Vittum in Photographic Science andEngineering, Vol. 13, p. 174 (1969), incorporated herein by reference.

[0122] It is common practice to coat one, two or three separate emulsionlayers within a single dye image-forming layer unit. When two or moreemulsion layers are coated in a single layer unit, they are typicallychosen to differ in sensitivity. When a more sensitive emulsion iscoated over a less sensitive emulsion, a higher speed is realized thanwhen the two emulsions are blended. When a less sensitive emulsion iscoated over a more sensitive emulsion, a higher contrast is realizedthan when the two emulsions are blended. It is preferred that the mostsensitive emulsion be located nearest the source of exposing radiationand the slowest emulsion be located nearest the support.

[0123] One or more of the layer units of the invention is preferablysubdivided into at least two, and more preferably three or more sub-unitlayers. It is preferred that all light sensitive silver halide emulsionsin the color recording unit have spectral sensitivity in the same regionof the visible spectrum. In this embodiment, while all silver halideemulsions incorporated in the unit have spectral absorptance accordingto invention, it is expected that there are minor differences inspectral absorptance properties between them. In still more preferredembodiments, the sensitizations of the slower silver halide emulsionsare specifically tailored to account for the light shielding effects ofthe faster silver halide emulsions of the layer unit that reside abovethem, in order to provide an imagewise uniform spectral response by thephotographic recording material as exposure varies with low to highlight levels. Thus higher proportions of peak light absorbing spectralsensitizing dyes may be desirable in the slower emulsions of thesubdivided layer unit to account for on-peak shielding and broadening ofthe underlying layer spectral sensitivity.

[0124] The interlayers IL1 and IL2 are hydrophilic colloid layers havingas their primary function color contamination reduction—i.e., preventionof oxidized developing agent from migrating to an adjacent recordinglayer unit before reacting with dye-forming coupler. The interlayers arein part effective simply by increasing the diffusion path length thatoxidized developing agent must travel. To increase the effectiveness ofthe interlayers to intercept oxidized developing agent, it isconventional practice to incorporate oxidized developing agent.Antistain agents (oxidized developing agent scavengers) can be selectedfrom among those disclosed by Research Disclosure I, X. Dye imageformers and modifiers, D. Hue modifiers/stabilization, paragraph (2).When one or more silver halide emulsions in GU and RU are high bromideemulsions and, hence have significant native sensitivity to blue light,it is preferred to incorporate a yellow filter, such as Carey Lea silveror a yellow processing solution decolorizable dye, in IL1. Suitableyellow filter dyes can be selected from among those illustrated byResearch Disclosure I, Section VIII. Absorbing and scattering materials,B. Absorbing materials. In elements of the instant invention, magentacolored filter materials are absent from IL2 and RU.

[0125] The antihalation layer unit AHU typically contains a lightabsorbing material that can be removed or decolorized during processing,such as one or a combination of pigments and dyes. Suitable materialscan be selected from among those disclosed in Research Disclosure I,Section VIII. Absorbing materials. A common alternative location for AHUis between the support S and the recording layer unit coated nearest thesupport.

[0126] The surface overcoats SOC are hydrophilic colloid layers that areprovided for physical protection of the color negative elements duringhandling and processing. Each SOC also provides a convenient locationfor incorporation of addenda that are most effective at or near thesurface of the color negative element. In some instances the surfaceovercoat is divided into a surface layer and an interlayer, the latterfunctioning as spacer between the addenda in the surface layer and theadjacent recording layer unit. In another common variant form, addendaare distributed between the surface layer and the interlayer, with thelatter containing addenda that are compatible with the adjacentrecording layer unit. Most typically the SOC contains addenda, such ascoating aids, plasticizers and lubricants, antistats and matting agents,such as illustrated by Research Disclosure I, Section IX. Coatingphysical property modifying addenda. The SOC overlying the emulsionlayers additionally preferably contains an ultraviolet absorber, such asillustrated by Research Disclosure I, Section VI, UV dyes/opticalbrighteners/luminescent dyes, paragraph (1).

[0127] Instead of the layer unit sequence of element SCN-1, alternativelayer units sequences can be employed and are particularly attractivefor some emulsion choices. Using high chloride emulsions and/or thin(<0.2 μm mean grain thickness) tabular grain emulsions all possibleinterchanges of the positions of BU, GU and RU can be undertaken withoutrisk of blue light contamination of the minus blue records, since theseemulsions exhibit negligible native sensitivity in the visible spectrum.For the same reason, it is unnecessary to incorporate blue lightabsorbers in the interlayers.

[0128] When the emulsion layers within a dye image-forming layer unitdiffer in speed, it is conventional practice to limit the incorporationof dye image-forming coupler in the layer of highest speed to less thana stoichiometric amount, based on silver. The function of the highestspeed emulsion layer is to create the portion of the characteristiccurve just above the minimum density—i.e., in an exposure region that isbelow the threshold sensitivity of the remaining emulsion layer orlayers in the layer unit. In this way, adding the increased granularityof the highest sensitivity speed emulsion layer to the dye image recordproduced is minimized without sacrificing imaging speed.

[0129] In the foregoing discussion the blue, green and red recordinglayer units are described as containing yellow, magenta and cyan imagedye-forming couplers, respectively, as is conventional practice in colornegative elements used for printing. The invention can be suitablyapplied to conventional color negative construction as illustrated.Color reversal film construction would take a similar form, with theexception that colored masking couplers would be completely absent; intypical forms, development inhibitor releasing couplers would also beabsent. In preferred embodiments, the color negative elements areintended exclusively for scanning to produce three separate electroniccolor records. Thus the actual hue of the image dye produced is of noimportance. What is essential is merely that the dye image produced ineach of the layer units be differentiable from that produced by each ofthe remaining layer units. To provide this capability of differentiationit is contemplated that each of the layer units contain one or more dyeimage-forming couplers chosen to produce image dye having an absorptionhalf-peak bandwidth lying in a different spectral region. It isimmaterial whether the blue, green or red recording layer unit forms ayellow, magenta or cyan dye having an absorption half peak bandwidth inthe blue, green or red region of the spectrum, as is conventional in acolor negative element intended for use in printing, or an absorptionhalf-peak bandwidth in any other convenient region of the spectrum,ranging from the near ultraviolet (300-400 nm) through the visible andthrough the near infrared (700-1200 nm), so long as the absorptionhalf-peak bandwidths of the image dye in the layer units extend oversubstantially non-coextensive wavelength ranges. The term “substantiallynon-coextensive wavelength ranges” means that each image dye exhibits anabsorption half-peak band width that extends over at least a 25(preferably 50) nm spectral region that is not occupied by an absorptionhalf-peak band width of another image dye. Ideally the image dyesexhibit absorption half-peak band widths that are mutually exclusive.

[0130] When a layer unit contains two or more emulsion layers differingin speed, it is possible to lower image granularity in the image to beviewed, recreated from an electronic record, by forming in each emulsionlayer of the layer unit a dye image which exhibits an absorptionhalf-peak band width that lies in a different spectral region than thedye images of the other emulsion layers of layer unit. This technique isparticularly well suited to elements in which the layer units aredivided into sub-units that differ in speed. This allows multipleelectronic records to be created for each layer unit, corresponding tothe differing dye images formed by the emulsion layers of the samespectral sensitivity. The digital record formed by scanning the dyeimage formed by an emulsion layer of the highest speed is used torecreate the portion of the dye image to be viewed lying just aboveminimum density. At higher exposure levels second and, optionally, thirdelectronic records can be formed by scanning spectrally differentiateddye images formed by the remaining emulsion layer or layers. Thesedigital records contain less noise (lower granularity) and can be usedin recreating the image to be viewed over exposure ranges above thethreshold exposure level of the slower emulsion layers. This techniquefor lowering granularity is disclosed in greater detail by Sutton U.S.Pat. No. 5,314,794, the disclosure of which is here incorporated byreference.

[0131] Each layer unit of the color negative elements of the inventionproduces a dye image characteristic curve gamma of less than 1.5, whichfacilitates obtaining an exposure latitude of at least 2.7 log E. Aminimum acceptable exposure latitude of a multicolor photographicelement is that which allows accurately recording the most extremewhites (e.g., a bride's wedding gown) and the most extreme blacks (e.g.,a bride groom's tuxedo) that are likely to arise in photographic use. Anexposure latitude of 2.6 log E can just accommodate the typical brideand groom wedding scene. An exposure latitude of at least 3.0 log E ispreferred, since this allows for a comfortable margin of error inexposure level selection by a photographer. Even larger exposurelatitudes are specifically preferred, since the ability to obtainaccurate image reproduction with larger exposure errors is realized.Whereas in color negative elements intended for printing, the visualattractiveness of the printed scene is often lost when gamma isexceptionally low, when color negative elements are scanned to createdigital dye image records, contrast can be increased by adjustment ofthe electronic signal information. When the elements of the inventionare scanned using a reflected beam, the beam travels through the layerunits twice. This effectively doubles gamma (ΔD÷Δlog E) by doublingchanges in density (ΔD). Thus, gamma's as low as 1.0 or even 0.6 arecontemplated and exposure latitudes of up to about 5.0 log E or higherare feasible. Gammas of about 0.55 are preferred. Gammas of betweenabout 0.4 and 0.5 are especially preferred.

[0132] Instead of employing dye-forming couplers, any of theconventional incorporated dye image generating compounds employed inmulticolor imaging can be alternatively incorporated in the blue, greenand red recording layer units. Dye images can be produced by theselective destruction, formation or physical removal of dyes as afunction of exposure. For example, silver dye bleach processes are wellknown and commercially utilized for forming dye images by the selectivedestruction of incorporated image dyes. The silver dye bleach process isillustrated by Research Disclosure I, Section X. Dye image formers andmodifiers, A. Silver dye bleach.

[0133] It is also well known that pre-formed image dyes can beincorporated in blue, green and red recording layer units, the dyesbeing chosen to be initially immobile, but capable of releasing the dyechromophore in a mobile moiety as a function of entering into a redoxreaction with oxidized developing agent. These compounds are commonlyreferred to as redox dye releasers (RDR's). By washing out the releasedmobile dyes, a retained dye image is created that can be scanned. It isalso possible to transfer the released mobile dyes to a receiver, wherethey are immobilized in a mordant layer. The image-bearing receiver canthen be scanned. Initially the receiver is an integral part of the colornegative element. When scanning is conducted with the receiver remainingan integral part of the element, the receiver typically contains atransparent support, the dye image bearing mordant layer just beneaththe support, and a white reflective layer just beneath the mordantlayer. Where the receiver is peeled from the color negative element tofacilitate scanning of the dye image, the receiver support can bereflective, as is commonly the choice when the dye image is intended tobe viewed, or transparent, which allows transmission scanning of the dyeimage. RDR's as well as dye image transfer systems in which they areincorporated are described in Research Disclosure, Vol. 151, November1976, Item 15162.

[0134] It is also recognized that the dye image can be provided bycompounds that are initially mobile, but are rendered immobile duringimagewise development. Image transfer systems utilizing imaging dyes ofthis type have long been used in previously disclosed dye image transfersystems. These and other image transfer systems compatible with thepractice of the invention are disclosed in Research Disclosure, Vol.176, December 1978, Item 17643, XXIII. Image transfer systems.

[0135] A number of modifications of color negative elements have beensuggested for accommodating scanning, as illustrated by ResearchDisclosure I, Section XIV. Scan facilitating features. These systems tothe extent compatible with the color negative element constructionsdescribed above are contemplated for use in the practice of thisinvention.

[0136] It is also contemplated that the imaging element of thisinvention may be used with non-conventional sensitization schemes. Forexample, instead of using imaging layers sensitized to the red, green,and blue regions of the spectrum, the light-sensitive material may haveone white-sensitive layer to record scene luminance, and twocolor-sensitive layers to record scene chrominance. Followingdevelopment, the resulting image can be scanned and digitallyreprocessed to reconstruct the full colors of the original scene asdescribed in U.S. Pat. No. 5,962,205. The imaging element may alsocomprise a pan-sensitized emulsion with accompanying color-separationexposure. In this embodiment, the developers of the invention would giverise to a colored or neutral image which, in conjunction with theseparation exposure, would enable full recovery of the original scenecolor values. In such an element, the image may be formed by eitherdeveloped silver density, a combination of one or more conventionalcouplers, or “black” couplers such as resorcinol couplers. Theseparation exposure may be made either sequentially through appropriatefilters, or simultaneously through a system of spatially discreet filterelements (commonly called a “color filter array”).

[0137] The imaging element of the invention may also be a black andwhite image-forming material comprised, for example, of a pan-sensitizedsilver halide emulsion and a developer of the invention. In thisembodiment, the image may be formed by developed silver densityfollowing processing, or by a coupler that generates a dye which can beused to carry the neutral image tone scale.

[0138] When conventional yellow, magenta, and cyan image dyes are formedto read out the recorded scene exposures following chemical developmentof conventional exposed color photographic materials, the response ofthe red, green, and blue color recording units of the element can beaccurately discerned by examining their densities. Densitometry is themeasurement of transmitted light by a sample using selected coloredfilters to separate the imagewise response of the RGB image dye formingunits into relatively independent channels. It is common to use Status Mfilters to gauge the response of color negative film elements intendedfor optical printing, and Status A filters for color reversal filmsintended for direct transmission viewing. In integral densitometry, theunwanted side and tail absorptions of the imperfect image dyes leads toa small amount of channel mixing, where part of the total response of,for example, a magenta channel may come from off-peak absorptions ofeither the yellow or cyan image dyes records, or both, in neutralcharacteristic curves. Such artifacts may be negligible in themeasurement of a film's spectral sensitivity. By appropriatemathematical treatment of the integral density response, these unwantedoff-peak density contributions can be completely corrected providinganalytical densities, where the response of a given color record isindependent of the spectral contributions of the other image dyes.Analytical density determination has been summarized in the SPSEHandbook of Photographic Science and Engineering, W. Thomas, editor,John Wiley and Sons, New York, 1973, Section 15.3, Color Densitometry,pp. 840-848.

[0139] Image noise can be reduced, where the images are obtained byscanning exposed and processed color negative film elements to obtain amanipulatable electronic record of the image pattern, followed byreconversion of the adjusted electronic record to a viewable form. Imagesharpness and colorfulness can be increased by designing layer gammaratios to be within a narrow range while avoiding or minimizing otherperformance deficiencies, where the color record is placed in anelectronic form prior to recreating a color image to be viewed. Whereasit is impossible to separate image noise from the remainder of the imageinformation, either in printing or by manipulating an electronic imagerecord, it is possible by adjusting an electronic image record thatexhibits low noise, as is provided by color negative film elements withlow gamma ratios, to improve overall curve shape and sharpnesscharacteristics in a manner that is impossible to achieve by knownprinting techniques. Thus, images can be recreated from electronic imagerecords derived from such color negative elements that are superior tothose similarly derived from conventional color negative elementsconstructed to serve optical printing applications. The excellentimaging characteristics of the described element are obtained when thegamma ratio for each of the red, green and blue color recording units isless than 1.2. In a more preferred embodiment, the red, green, and bluelight sensitive color forming units each exhibit gamma ratios of lessthan 1.15. In an even more preferred embodiment, the red and blue lightsensitive color forming units each exhibit gamma ratios of less than1.10. In a most preferred embodiment, the red, green, and blue lightsensitive color forming units each exhibit gamma ratios of less than1.10. In all cases, it is preferred that the individual color unit(s)exhibit gamma ratios of less than 1.15, more preferred that they exhibitgamma ratios of less than 1.10 and even more preferred that they exhibitgamma ratios of less than 1.05. The gamma ratios of the layer units neednot be equal. These low values of the gamma ratio are indicative of lowlevels of interlayer interaction, also known as interlayer interimageeffects, between the layer units and are believed to account for theimproved quality of the images after scanning and electronicmanipulation. The apparently deleterious image characteristics thatresult from chemical interactions between the layer units need not beelectronically suppressed during the image manipulation activity. Theinteractions are often difficult if not impossible to suppress properlyusing known electronic image manipulation schemes.

[0140] Elements having excellent light sensitivity are best employed inthe practice of this invention. The elements should have a sensitivityof at least about ISO 50, preferably have a sensitivity of at leastabout ISO 100, and more preferably have a sensitivity of at least aboutISO 200. Elements having a sensitivity of up to ISO 3200 or even higherare specifically contemplated. The speed, or sensitivity, of a colornegative photographic element is inversely related to the exposurerequired to enable the attainment of a specified density above fog afterprocessing. Photographic speed for a color negative element with a gammaof about 0.65 in each color record has been specifically defined by theAmerican National Standards Institute (ANSI) as ANSI Standard Number PH2.27-1981 (ISO (ASA Speed)) and relates specifically the average ofexposure levels required to produce a density of 0.15 above the minimumdensity in each of the green light sensitive and least sensitive colorrecording unit of a color film. This definition conforms to theInternational Standards Organization (ISO) film speed rating. For thepurposes of this application, if the color unit gammas differ from 0.65,the ASA or ISO speed is to be calculated by linearly amplifying ordeamplifying the gamma vs. log E (exposure) curve to a value of 0.65before determining the speed in the otherwise defined manner.

[0141] The present invention also contemplates the use of photographicelements of the present invention in what are often referred to assingle use cameras (or “film with lens” units). These cameras are soldwith film preloaded in them and the entire camera is returned to aprocessor with the exposed film remaining inside the camera. Theone-time-use cameras employed in this invention can be any of thoseknown in the art. These cameras can provide specific features as knownin the art such as shutter means, film winding means, film advancemeans, waterproof housings, single or multiple lenses, lens selectionmeans, variable aperture, focus or focal length lenses, means formonitoring lighting conditions, means for adjusting shutter times orlens characteristics based on lighting conditions or user providedinstructions, and means for camera recording use conditions directly onthe film. These features include, but are not limited to: providingsimplified mechanisms for manually or automatically advancing film andresetting shutters as described at Skarman, U.S. Pat. No. 4,226,517;providing apparatus for automatic exposure control as described atMatterson et al, U.S. Pat. No. 4,345,835; moisture-proofing as describedat Fujimura et al, U.S. Pat. No. 4,766,451; providing internal andexternal film casings as described at Ohmura et al, U.S. Pat. No.4,751,536; providing means for recording use conditions on the film asdescribed at Taniguchi et al, U.S. Pat. No. 4,780,735; providing lensfitted cameras as described at Arai, U.S. Pat. No. 4,804,987; providingfilm supports with superior anti-curl properties as described at Sasakiet al, U.S. Pat. No. 4,827,298; providing a viewfinder as described atOhmura et al, U.S. Pat. No. 4,812,863; providing a lens of defined focallength and lens speed as described at Ushiro et al, U.S. Pat. No.4,812,866; providing multiple film containers as described at Nakayamaet al, U.S. Pat. No. 4,831,398 and at Ohmura et al, U.S. Pat. No.4,833,495; providing films with improved anti-friction characteristicsas described at Shiba, U.S. Pat. No. 4,866,469; providing windingmechanisms, rotating spools, or resilient sleeves as described atMochida, U.S. Pat. No. 4,884,087; providing a film patrone or cartridgeremovable in an axial direction as described by Takei et al at U.S. Pat.Nos. 4,890,130 and 5,063,400; providing an electronic flash means asdescribed at Ohmura et al, U.S. Pat. No. 4,896,178; providing anexternally operable member for effecting exposure as described atMochida et al, U.S. Pat. No. 4,954,857; providing film support withmodified sprocket holes and means for advancing said film as describedat Murakami, U.S. Pat. No. 5,049,908; providing internal mirrors asdescribed at Hara, U.S. Pat. No. 5,084,719; and providing silver halideemulsions suitable for use on tightly wound spools as described at Yagiet al, European Patent Application 0,466,417 A.

[0142] While the film may be mounted in the one-time-use camera in anymanner known in the art, it is especially preferred to mount the film inthe one-time-use camera such that it is taken up on exposure by a thrustcartridge. Thrust cartridges are disclosed by Kataoka et al U.S. Pat.No. 5,226,613; by Zander U.S. Pat. No. 5,200,777; by Dowling et al U.S.Pat. No. 5,031,852; and by Robertson et al U.S. Pat. No. 4,834,306.Narrow bodied one-time-use cameras suitable for employing thrustcartridges in this way are described by Tobioka et al U.S. Pat. No.5,692,221. More generally, the size limited cameras most useful asone-time-use cameras will be generally rectangular in shape and can meetthe requirements of easy handling and transportability in, for example,a pocket, when the camera as described herein has a limited volume. Thecamera should have a total volume of less than about 450 cubiccentimeters (cc's), preferably less than 380 cc, more preferably lessthan 300 cc, and most preferably less than 220 cc. Thedepth-to-height-to-length proportions of such a camera will generally bein an about 1:2:4 ratio, with a range in each of about 25% so as toprovide comfortable handling and pocketability. Generally the minimumusable depth is set by the focal length of the incorporated lens and bythe dimensions of the incorporated film spools and cartridge. The camerawill preferably have the majority of corners and edges finished with aradius-of-curvature of between about 0.2 and 3 centimeters. The use ofthrust cartridges allows a particular advantage in this invention byproviding easy scanner access to particular scenes photographed on aroll while protecting the film from dust, scratches, and abrasion, allof which tend to degrade the quality of an image.

[0143] While any known taking lens may be employed in the cameras ofthis invention, the taking lens mounted on the single-use cameras of theinvention are preferably single aspherical plastic lenses. The lenseswill have a focal length between about 10 and 100 mim, and a lensaperture between f/2 and f/32. The focal length is preferably betweenabout 15 and 60 mm and most preferably between about 20 and 40 mm. Forpictorial applications, a focal length matching to within 25% thediagonal of the rectangular film exposure area is preferred. Lensapertures of between f/2.8 and f/22 are contemplated with a lensaperture of about f/4 to f/16 being preferred. The lens MTF can be aslow as 0.6 or less at a spatial frequency of 20 lines per millimeter (1pm) at the film plane, although values as high as 0.7 or most preferably0.8 or more are contemplated. Higher lens MTF values generally allowsharper pictures to be produced. Multiple lens arrangements comprisingtwo, three, or more component lens elements consistent with thefunctions described above are specifically contemplated.

[0144] Cameras may contain a built-in processing capability, for examplea heating element. Designs for such cameras including their use in animage capture and display system are disclosed in U.S. patentapplication Ser. No. 09/388,573 filed Sep. 1, 1999, incorporated hereinby reference. The use of a one-time use camera as disclosed in saidapplication is particularly preferred in the practice of this invention.

[0145] Photographic elements of the present invention are preferablyimagewise exposed using any of the known techniques, including thosedescribed in Research Disclosure I, Section XVI. This typically involvesexposure to light in the visible region of the spectrum, and typicallysuch exposure is of a live image through a lens, although exposure canalso be exposure to a stored image (such as a computer stored image) bymeans of light emitting devices (such as light emitting diodes, CRT andthe like). The photothermographic elements are also exposed by means ofvarious forms of energy, including ultraviolet and infrared regions ofthe electromagnetic spectrum as well as electron beam and betaradiation, gamma ray, x-ray, alpha particle, neutron radiation and otherforms of corpuscular wave-like radiant energy in either non-coherent(random phase) or coherent (in phase) forms produced by lasers.Exposures are monochromatic, orthochromatic, or panchromatic dependingupon the spectral sensitization of the photographic silver halide.

[0146] The elements as discussed above may serve as origination materialfor some or all of the following processes: image scanning to produce anelectronic rendition of the capture image, and subsequent digitalprocessing of that rendition to manipulate, store, transmit, output, ordisplay electronically that image.

[0147] The blocked compounds of this invention may be used inphotographic elements that contain any or all of the features discussedabove, but are intended for different forms of processing. These typesof systems will be described in detail below.

[0148] Type I: Thermal process systems (thermographic andphotothermographic), where processing is initiated solely by theapplication of heat to the imaging element.

[0149] Type II: Low volume systems, where film processing is initiatedby contact to a processing solution, but where the processing solutionvolume is comparable to the total volume of the imaging layer to beprocessed. This type of system may include the addition of non solutionprocessing aids, such as the application of heat or of a laminate layerthat is applied at the time of processing.

[0150] Type III: Conventional photographic systems, where film elementsare processed by contact with conventional photographic processingsolutions, and the volume of such solutions is very large in comparisonto the volume of the imaging layer.

Type I: Thermographic and Photothermographic Systems

[0151] In accordance with one aspect of this invention the blockeddeveloper is incorporated in a photothermographic element.Photothermographic elements of the type described in Research Disclosure17029 are included by reference. The photothermographic elements may beof type A or type B as disclosed in Research Disclosure 17029. Type Aelements contain in reactive association a photosensitive silver halide,a reducing agent or developer, an activator, and a coating vehicle orbinder. In these systems development occurs by reduction of silver ionsin the photosensitive silver halide to metallic silver. Type B systemscan contain all of the elements of a type A system in addition to a saltor complex of an organic compound with silver ion. In these systems,this organic complex is reduced during development to yield silvermetal. The organic silver salt will be referred to as the silver donor.References describing such imaging elements include, for example, U.S.Pat. Nos. 3,457,075; 4,459,350; 4,264,725 and 4,741,992.

[0152] The photothermographic element comprises a photosensitivecomponent that consists essentially of photographic silver halide. Inthe type B photothermographic material it is believed that the latentimage silver from the silver halide acts as a catalyst for the describedimage-forming combination upon processing. In these systems, a preferredconcentration of photographic silver halide is within the range of 0.01to 100 moles of photographic silver halide per mole of silver donor inthe photothermographic material.

[0153] The Type B photothermographic element comprises anoxidation-reduction image forming combination that contains an organicsilver salt oxidizing agent. The organic silver salt is a silver saltwhich is comparatively stable to light, but aids in the formation of asilver image when heated to 80° C. or higher in the presence of anexposed photocatalyst (i.e., the photosensitive silver halide) and areducing agent.

[0154] Suitable organic silver salts include silver salts of organiccompounds having a carboxyl group. Preferred examples thereof include asilver salt of an aliphatic carboxylic acid and a silver salt of anaromatic carboxylic acid. Preferred examples of the silver salts ofaliphatic carboxylic acids include silver behenate, silver stearate,silver oleate, silver laureate, silver caprate, silver myristate, silverpalmitate, silver maleate, silver fumarate, silver tartarate, silverfuroate, silver linoleate, silver butyrate and silver camphorate,mixtures thereof, etc. Silver salts which are substitutable with ahalogen atom or a hydroxyl group can also be effectively used. Preferredexamples of the silver salts of aromatic carboxylic acid and othercarboxyl group-containing compounds include silver benzoate, asilver-substituted benzoate such as silver 3,5-dihydroxybenzoate, silvero-methylbenzoate, silver m-methylbenzoate, silver p-methylbenzoate,silver 2,4-dichlorobenzoate, silver acetamidobenzoate, silverp-phenylbenzoate, etc., silver gallate, silver tannate, silverphthalate, silver terephthalate, silver salicylate, silverphenylacetate, silver pyromellilate, a silver salt of3-carboxymethyl-4-methyl-4-thiazoline-2-thione or the like as describedin U.S. Pat. No. 3,785,830, and silver salt of an aliphatic carboxylicacid containing a thioether group as described in U.S. Pat. No.3,330,663.

[0155] Silver salts of mercapto or thione substituted compounds having aheterocyclic nucleus containing 5 or 6 ring atoms, at least one of whichis nitrogen, with other ring atoms including carbon and up to twohetero-atoms selected from among oxygen, sulfur and nitrogen arespecifically contemplated. Typical preferred heterocyclic nuclei includetriazole, tetrazole, oxazole, thiazole, thiazoline,, imidazoline,imidazole, diazole, pyridine and triazine. Preferred examples of theseheterocyclic compounds include a silver salt of3-mercapto-4-phenyl-1,2,4 triazole, a silver salt of1-phenyl-5-mercaptotetrazole, a silver salt of 2-mercaptobenzimidazole,a silver salt of 2-mercapto-5-aminothiadiazole, a silver salt of2-(2-ethyl-glycolamido)benzothiazole, a silver salt of5-carboxylic-1-methyl-2-phenyl-4-thiopyridine, a silver salt ofmercaptotriazine, a silver salt of 2-mercaptobenzoxazole, a silver saltas described in U.S. Pat. No. 4,123,274, for example, a silver salt of1,2,4-mercaptothiazole derivative such as a silver salt of3-amino-5-benzylthio-1, 2,4-thiazole, a silver salt of a thione compoundsuch as a silver salt of3-(2-carboxyethyl)-4-methyl-4-thiazoline-2-thione as disclosed in U.S.Pat. No. 3,201,678. Examples of other useful mercapto or thionesubstituted compounds that do not contain a heterocyclic nucleus areillustrated by the following: a silver salt of thioglycolic acid such asa silver salt of a S-alkylthioglycolic acid (wherein the alkyl group hasfrom 12 to 22 carbon atoms) as described in Japanese patent application28221/73, a silver salt of a dithiocarboxylic acid such as a silver saltof dithioacetic acid, and a silver salt of thioamide.

[0156] Furthermore, a silver salt of a compound containing an iminogroup can be used. Preferred examples of these compounds include asilver salt of benzotriazole and a derivative thereof as described inJapanese patent publications 30270/69 and 18146/70, for example a silversalt of benzotriazole or methylbenzotriazole, etc., a silver salt of ahalogen substituted benzotriazole, such as a silver salt of5-chlorobenzotriazole, etc., a silver salt of 1,2,4-triazole, a silversalt of 3-amino-5-mercaptobenzyl-1,2,4-triazole, of 1H-tetrazole asdescribed in U.S. Pat. No. 4,220,709, a silver salt of imidazole and animidazole derivative, and the like.

[0157] It is also found convenient to use silver half soap, of which anequimolar blend of a silver behenate with behenic acid, prepared byprecipitation from aqueous solution of the sodium salt of commercialbehenic acid and analyzing about 14.5 percent silver, represents apreferred example. Transparent sheet materials made on transparent filmbacking require a transparent coating and for this purpose the silverbehenate full soap, containing not more than about 4 or 5 percent offree behenic acid and analyzing about 25.2 percent silver may be used. Amethod for making silver soap dispersions is well known in the art andis disclosed in Research Disclosure October 1983 (23419) and U.S. Pat.No. 3,985,565.

[0158] Silver salts complexes may also be prepared by mixture of aqueoussolutions of a silver ionic species, such as silver nitrate, and asolution of the organic ligand to be complexed with silver. The mixtureprocess may take any convenient form, including those employed in theprocess of silver halide precipitation. A stabilizer may be used toavoid flocculation of the silver complex particles. The stabilizer maybe any of those materials known to be useful in the photographic art,such as, but not limited to, gelatin, polyvinyl alcohol or polymeric ormonomeric surfactants.

[0159] The photosensitive silver halide grains and the organic silversalt are coated so that they are in catalytic proximity duringdevelopment. They can be coated in contiguous layers, but are preferablymixed prior to coating. Conventional mixing techniques are illustratedby Research Disclosure, Item 17029, cited above, as well as U.S. Pat.No. 3,700,458 and published Japanese patent applications Nos. 32928/75,13224/74, 17216/75 and 42729/76.

[0160] A reducing agent in addition to the blocked developer may beincluded. The reducing agent for the organic silver salt may be anymaterial, preferably organic material, that can reduce silver ion tometallic silver. Conventional photographic developers such as3-pyrazolidinones, hydroquinones, p-aminophenols, p-phenylenediaminesand catechol are useful, but hindered phenol reducing agents arepreferred. The reducing agent is preferably present in a concentrationranging from 5 to 25 percent of the photothermographic layer.

[0161] A wide range of reducing agents has been disclosed in dry silversystems including amidoximes such as phenylarnidoxime,2-thienylamidoxime and p-phenoxy-phenylamidoxime, azines (e.g.,4-hydroxy-3,5-dimethoxybenzaldehydeazine); a combination of aliphaticcarboxylic acid aryl hydrazides and ascorbic acid, such as2,2′-bis(hydroxymethyl)propionylbetaphenyl hydrazide in combination withascorbic acid; an combination of polyhydroxybenzene and hydroxylamine, areductone and/or a hydrazine, e.g., a combination of hydroquinone andbis(ethoxyethyl)hydroxylamine, piperidinohexose reductone orformyl-4-methylphenylhydrazine, hydroxamic acids such asphenylhydroxamic acid, p-hydroxyphenyl-hydroxamic acid, ando-alaninehydroxamic acid; a combination of azines andsulfonamidophenols, e.g., phenothiazine and2,6-dichloro-4-benzenesulfonamidophenol; α-cyano-phenylacetic acidderivatives such as ethyl αcyano-2-methylphenylacetate, ethylα-cyano-phenylacetate; bis-μ-naphthols as illustrated by2,2′-dihydroxyl-1-binaphthyl, 6,6′-dibromo-2,2′-dihydroxy-1,1′-binaphthyl, and bis(2-hydroxy-1-naphthyl)methane; a combination ofbis-β-naphthol and a 1,3-dihydroxybenzene derivative, (e. g.,2,4-dihydroxybenzophenone or 2,4-dihydroxyacetophenone); 5-pyrazolonessuch as 3-methyl-1-phenyl-5-pyrazolone; reductones as illustrated bydimethylaminohexose reductone, anhydrodihydroaminohexose reductone, andanhydrodihydro-piperidone-hexose reductone; sulfamidophenol reducingagents such as 2,6-dichloro-4-benzene-sulfon-amido-phenol, andp-benzenesulfonamidophenol; 2-phenylindane-1, 3-dione and the like;chromans such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman;1,4-dihydropyridines such as 2,6-dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridene; bisphenols, e.g.,bis(2-hydroxy-3-t-butyl-5-methylphenyl)-methane; 2,2-bis(4-hydroxy-3-methylphenyl)-propane; 4,4-ethylidene-bis(2-t-butyl-6-methylphenol);and 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane; ascorbic acidderivatives, e.g., 1-ascorbyl-palmitate, ascorbylstearate andunsaturated aldehydes and ketones, such as benzyl and diacetyl;pyrazolidin-3-ones; and certain indane-1,3-diones.

[0162] An optimum concentration of organic reducing agent in thephotothermographic element varies depending upon such factors as theparticular photothermographic element, desired image, processingconditions, the particular organic silver salt and the particularoxidizing agent.

[0163] The photothermographic element can comprise a toning agent, alsoknown as an activator-toner or toner-accelerator. Combinations of toningagents are also useful in the photothermographic element. Examples ofuseful toning agents and toning agent combinations are described in, forexample, Research Disclosure, June 1978, Item No. 17029 and U.S. Pat.No. 4,123,282. Examples of useful toning agents include, for example,phthalimide, N-hydroxyphthalimide, N-potassium-phthalimide, succinimide,N-hydroxy- 1,8-naphthalimide, phthalazine, 1-(2H)-phthalazinone,2-acetylphthalazinone, salicylanilide, benzamide, and dimethylurea.

[0164] Post-processing image stabilizers and latent image keepingstabilizers are useful in the photothennographic element. Any of thestabilizers known in the photothermographic art are usefuil for thedescribed photothermographic element. Illustrative examples of usefulstabilizers include photolytically active stabilizers and stabilizerprecursors as described in, for example, U.S. Pat. No. 4,459,350. Otherexamples of useful stabilizers include azole thioethers and blockedazolinethione stabilizer precursors and carbamoyl stabilizer precursors,such as described in U.S. Pat. No. 3,877,940.

[0165] The photothermographic elements preferably contain variouscolloids and polymers alone or in combination as vehicles and bindersand in various layers. Useful materials are hydrophilic or hydrophobic.They are transparent or translucent and include both naturally occurringsubstances, such as gelatin, gelatin derivatives, cellulose derivatives,polysaccharides, such as dextran, gum arabic and the like; and syntheticpolymeric substances, such as water-soluble polyvinyl compounds likepoly(vinylpyrrolidone) and acrylamide polymers. Other syntheticpolymeric compounds that are useful include dispersed vinyl compoundssuch as in latex form and particularly those that increase dimensionalstability of photographic elements. Effective polymers include waterinsoluble polymers of acrylates, such as alkylacrylates andmethacrylates, acrylic acid, sulfoacrylates, and those that havecross-linking sites. Preferred high molecular weight materials andresins include poly(vinyl butyral), cellulose acetate butyrate,poly(methylmethacrylate), poly(vinylpyrrolidone), ethyl cellulose,polystyrene, poly(vinylchloride), chlorinated rubbers, polyisobutylene,butadiene-styrene copolymers, copolymers of vinyl chloride and vinylacetate, copolymers of vinylidene chloride and vinyl acetate, poly(vinylalcohol) and polycarbonates. When coatings are made using organicsolvents, organic soluble resins may be coated by direct mixture intothe coating formulations. When coating from aqueous solution, any usefulorganic soluble materials may be incorporated as a latex or other fineparticle dispersion.

[0166] Photothermographic elements as described can contain addenda thatare known to aid in formation of a useful image. The photothermographicelement can contain development modifiers that function as speedincreasing compounds, sensitizing dyes, hardeners, antistatic agents,plasticizers and lubricants, coating aids, brighteners, absorbing andfilter dyes, such as described in Research Disclosure, December 1978,Item No. 17643 and Research Disclosure, June 1978, Item No. 17029.

[0167] The layers of the photothermographic element are coated on asupport by coating procedures known in the photographic art, includingdip coating, air knife coating, curtain coating or extrusion coatingusing hoppers. If desired, two or more layers are coated simultaneously.

[0168] A photothermographic element as described preferably comprises athermal stabilizer to help stabilize the photothermographic elementprior to exposure and processing. Such a thermal stabilizer providesimproved stability of the photothermographic element during storage.Preferred thermal stabilizers are 2-bromo-2-arylsulfonylacetamides, suchas 2-bromo-2-p-tolysulfonylacetamide; 2-(tribromomethylsulfonyl)benzothiazole; and6-substituted-2,4-bis(tribromomethyl)-s-triazines, such as 6-methyl or6-phenyl-2,4-bis(tribromomethyl)-s-triazine.

[0169] Imagewise exposure is preferably for a time and intensitysufficient to produce a developable latent image in thephotothermographic element.

[0170] After imagewise exposure of the photothermographic element, theresulting latent image can be developed in a variety of ways. Thesimplest is by overall heating the element to thermal processingtemperature. This overall heating merely involves heating thephotothermographic element to a temperature within the range of about90° C. to about 180° C. until a developed image is formed, such aswithin about 0.5 to about 60 seconds. By increasing or decreasing thethermal processing temperature a shorter or longer time of processing isuseful. A preferred thermal processing temperature is within the rangeof about 100° C. to about 160° C. Heating means known in thephotothermographic arts are useful for providing the desired processingtemperature for the exposed photothermographic element. The heatingmeans is, for example, a simple hot plate, iron, roller, heated drum,microwave heating means, heated air, vapor or the like.

[0171] It is contemplated that the design of the processor for thephotothermographic element be linked to the design of the cassette orcartridge used for storage and use of the element. Further, data storedon the film or cartridge may be used to modify processing conditions orscanning of the element. Methods for accomplishing these steps in theimaging system are disclosed in commonly assigned, co-pending U.S.patent applications Ser. Nos. 09/206586, 09/206,612, and 09/206,583filed Dec. 7, 1998, which are incorporated herein by reference. The useof an apparatus whereby the processor can be used to write informationonto the element, information which can be used to adjust processing,scanning, and image display is also envisaged. This system is disclosedin U.S. patent applications Ser. Nos. 09/206,914 filed Dec. 7, 1998 and09/333,092 filed Jun. 15, 1999, which are incorporated herein byreference.

[0172] Thermal processing is preferably carried out under ambientconditions of pressure and humidity. Conditions outside of normalatmospheric pressure and humidity are useful.

[0173] The components of the photothermographic element can be in anylocation in the element that provides the desired image. If desired, oneor more of the components can be in one or more layers of the element.For example, in some cases, it is desirable to include certainpercentages of the reducing agent, toner, stabilizer and/or otheraddenda in the overcoat layer over the photothermographic imagerecording layer of the element. This, in some cases, reduces migrationof certain addenda in the layers of the element.

[0174] In accordance with one aspect of this invention the blocked PUGis incorporated in a thermographic element, in which the PUG can be adeveloper or a preformed leuco or shifted dye. In thermographic elementsan image is formed by imagewise heating the element. Such elements aredescribed in, for example, Research Disclosure, Jun. 1978, Item No.17029 and U.S. Pat. Nos. 3,080,254, 3,457,075 and 3,933,508, thedisclosures or which are incorporated herein by reference. The thermalenergy source and means for imaging can be any imagewise thermalexposure source and means that are known in the thermographic imagingart. The thermographic imaging means can be, for example, an infraredheating means, laser, microwave heating means or the like.

Type II: Low Volume Processing

[0175] In accordance with another aspect of this invention the blockeddeveloper is incorporated in a photographic element intended for lowvolume processing. Low volume processing is defined as processing wherethe volume of applied developer solution is between about 0.1 to about10 times, preferably about 0.5 to about 10 times, the volume of solutionrequired to swell the photographic element. This processing may takeplace by a combination of solution application, external layerlamination, and heating. The low volume processing system may containany of the elements described above for Type I: Photothermographicsystems. In addition, it is specifically contemplated that anycomponents described in the preceding sections that are not necessaryfor the formation or stability of latent image in the origination filmelement can be removed from the film element altogether and contacted atany time after exposure for the purpose of carrying out photographicprocessing, using the methods described below.

[0176] The Type II photographic element may receive some or all of thefollowing treatments:

[0177] (I) Application of a solution directly to the film by any means,including spray, inkjet, coating, gravure process and the like.

[0178] (II) Soaking of the film in a reservoir containing a processingsolution. This process may also take the form of dipping or passing anelement through a small cartridge.

[0179] (III) Lamination of an auxiliary processing element to theimaging element. The laminate may have the purpose of providingprocessing chemistry, removing spent chemistry, or transferring imageinformation from the latent image recording film element. Thetransferred image may result from a dye, dye precursor, or silvercontaining compound being transferred in a image-wise manner to theauxiliary processing element.

[0180] (IV) Heating of the element by any convenient means, including asimple hot plate, iron, roller, heated drum, microwave heating means,heated air, vapor, or the like. Heating may be accomplished before,during, after, or throughout any of the preceding treatments I-III.Heating may cause processing temperatures ranging from room temperatureto 100° C.

Type III: Conventional Systems

[0181] In accordance with another aspect of this invention the blockeddeveloper is incorporated in a conventional photographic element.

[0182] Conventional photographic elements in accordance with theinvention can be processed in any of a number of well-known photographicprocesses utilizing any of a number of well-known conventionalphotographic processing solutions, described, for example, in ResearchDisclosure I, or in T. H. James, editor, The Theory of the PhotographicProcess, 4th Edition, Macmillan, N.Y., 1977. The development process maytake place for any length of time and any process temperature that issuitable to render an acceptable image. In these cases the presence ofblocked developers of the invention may be used to provide developmentin one or more color records of the element, supplementary to thedevelopment provided by the developer in the processing solution to giveimproved signal in a shorter time of development or with loweredlaydowns of imaging materials, or to give balanced development in allcolor records. In the case of processing a negative working element, theelement is treated with a color developer (that is one which will formthe colored image dyes with the color couplers), and then with aoxidizer and a solvent to remove silver and silver halide. In the caseof processing a reversal color element, the element is first treatedwith a black and white developer (that is, a developer which does notform colored dyes with the coupler compounds) followed by a treatment tofog silver halide (usually chemical fogging or light fogging), followedby treatment with a color developer. Preferred color developing agentsare p-phenylenediamines. Especially preferred are:

[0183] 4-amino N,N-diethylaniline hydrochloride,

[0184] 4-amino-3-methyl-N,N-diethylaniline hydrochloride,

[0185] 4-amino-3-methyl-N-ethyl-N-(2-(methanesulfonamido) ethylanilinesesquisulfate hydrate,

[0186] 4-amino-3-methyl-N-ethyl-N-(2-hydroxyethyl)aniline sulfate,

[0187] 4-amino-3-α-(methanesulfonamido)ethyl-N,N-diethylanilinehydrochloride and

[0188] 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluenesulfonic acid.

[0189] Dye images can be formed or amplified by processes which employin combination with a dye-image-generating reducing agent an inerttransition metal-ion complex oxidizing agent, as illustrated byBissonette U.S. Pat. Nos. 3,748,138, 3,826,652, 3,862,842 and 3,989,526and Travis U.S. Pat. No. 3,765,891, and/or a peroxide oxidizing agent asillustrated by Matejec U.S. Pat. No. 3,674,490, Research Disclosure,Vol. 116, December, 1973, Item 11660, and Bissonette ResearchDisclosure, Vol. 148, August, 1976, Items 14836, 14846 and 14847. Thephotographic elements can be particularly adapted to form dye images bysuch processes as illustrated by Dunn et al U.S. Pat. No. 3,822,129,Bissonette U.S. Pat. Nos. 3,834,907 and 3,902,905, Bissonette et al U.S.Pat. No. 3,847,619, Mowrey U.S. Pat. No. 3,904,413, Hirai et al U.S.Pat. No. 4,880,725, Iwano U.S. Pat. No. 4,954,425, Marsden et al U.S.Pat. No. 4,983,504, Evans et al U.S. Pat. No. 5,246,822, Twist U.S. Pat.No. 5,324,624, Fyson EPO 0 487 616, Tannahill et al WO 90/13059, Marsdenet al WO 90/13061, Grimsey et al WO 91/16666, Fyson WO 91/17479, Marsdenet al WO 92/01972. Tannahill WO 92/05471, Henson WO 92/07299, Twist WO93/01524 and WO 93/11460 and Wingender et al German OLS 4,211,460.

[0190] Development may be followed by bleach-fixing, to remove silver orsilver halide, washing and drying.

[0191] Once yellow, magenta, and cyan dye image records have been formedin the processed photographic elements of the invention, conventionaltechniques can be employed for retrieving the image information for eachcolor record and manipulating the record for subsequent creation of acolor balanced viewable image. For example, it is possible to scan thephotographic element successively within the blue, green, and redregions of the spectrum or to incorporate blue, green, and red lightwithin a single scanning beam that is divided and passed through blue,green, and red filters to form separate scanning beams for each colorrecord. A simple technique is to scan the photographic elementpoint-by-point along a series of laterally offset parallel scan paths.The intensity of light passing through the element at a scanning pointis noted by a sensor which converts radiation received into anelectrical signal. Most generally this electronic signal is furthermanipulated to form a useful electronic record of the image. Forexample, the electrical signal can be passed through ananalog-to-digital converter and sent to a digital computer together withlocation information required for pixel (point) location within theimage. In another embodiment, this electronic signal is encoded withcalorimetric or tonal information to form an electronic record that issuitable to allow reconstruction of the image into viewable forms suchas computer monitor displayed images, television images, printed images,and so forth.

[0192] It is contemplated that many of imaging elements of thisinvention will be scanned prior to the removal of silver halide from theelement. The remaining silver halide yields a turbid coating, and it isfound that improved scanned image quality for such a system can beobtained by the use of scanners that employ diffuse illumination optics.Any technique known in the art for producing diffuse illumination can beused. Preferred systems include reflective systems, that employ adiffusing cavity whose interior walls are specifically designed toproduce a high degree of diffuse reflection, and transmissive systems,where diffusion of a beam of specular light is accomplished by the useof an optical element placed in the beam that serves to scatter light.Such elements can be either glass or plastic that either incorporate acomponent that produces the desired scattering, or have been given asurface treatment to promote the desired scattering.

[0193] One of the challenges encountered in producing images frominformation extracted by scanning is that the number of pixels ofinformation available for viewing is only a fraction of that availablefrom a comparable classical photographic print. It is, therefore, evenmore important in scan imaging to maximize the quality of the imageinformation available. Enhancing image sharpness and minimizing theimpact of aberrant pixel signals (i.e., noise) are common approaches toenhancing image quality. A conventional technique for minimizing theimpact of aberrant pixel signals is to adjust each pixel density readingto a weighted average value by factoring in readings from adjacentpixels, closer adjacent pixels being weighted more heavily.

[0194] The elements of the invention can have density calibrationpatches derived from one or more patch areas on a portion of unexposedphotographic recording material that was subjected to referenceexposures, as described by Wheeler et al U.S. Pat. No. 5,649,260, Koengat al U.S. Pat. No. 5,563,717, and by Cosgrove et al U.S. Pat.5,644,647.

[0195] Illustrative systems of scan signal manipulation, includingtechniques for maximizing the quality of image records, are disclosed byBayer U.S. Pat. No. 4,553,156; Urabe et al U.S. Pat. No. 4,591,923;Sasaki et al U.S. Pat. No. 4,631,578; Alkofer U.S. Pat. No. 4,654,722;Yamada et al U.S. Pat. No. 4,670,793; Klees U.S. Pat. Nos. 4,694,342 and4,962,542; Powell U.S. Pat. No. 4,805,031; Mayne et al U.S. Pat. No.4,829,370; Abdulwahab U.S. Pat. No. 4,839,721; Matsunawa et al U.S. Pat.Nos. 4,841,361 and 4,937,662; Mizukoshi et al U.S. Pat. No. 4,891,713;Petilli U.S. Pat. No. 4,912,569; Sullivan et al U.S. Pat. Nos. 4,920,501and 5,070,413; Kimoto et al U.S. Pat. No. 4,929,979; Hirosawa et al U.S.Pat. No. 4,972,256; Kaplan U.S. Pat. No. 4,977,521; Sakai U.S. Pat. No.4,979,027; Ng U.S. Pat. No. 5,003,494; Katayama et al U.S. Pat. No.5,008,950; Kimura et al U.S. Pat. No. 5,065,255; Osamu et al U.S. Pat.No. 5,051,842; Lee et al U.S. Pat. No. 5,012,333; Bowers et al U.S. Pat.No. 5,107,346; Telle U.S. Pat. No. 5,105,266; MacDonald et al U.S. Pat.No. 5,105,469; and Kwon et al U.S. Pat. No. 5,081,692. Techniques forcolor balance adjustments during scanning are disclosed by Moore et alU.S. Pat. No. 5,049,984 and Davis U.S. Pat. No. 5,541,645.

[0196] The digital color records once acquired are in most instancesadjusted to produce a pleasingly color balanced image for viewing and topreserve the color fidelity of the image bearing signals through varioustransformations or renderings for outputting, either on a video monitoror when printed as a conventional color print. Preferred techniques fortransforming image bearing signals after scanning are disclosed byGiorgianni et al U.S. Pat. No. 5,267,030, the disclosures of which areherein incorporated by reference. The signal transformation techniquesof Giorgianni et al '030 described in connection with FIG. 8 represent aspecifically preferred technique for obtaining a color balanced imagefor viewing. Further illustrations of the capability of those skilled inthe art to manage color digital image information are provided byGiorgianni and Madden Digital Color Management, Addison-Wesley, 1998.

EXAMPLE 1

[0197] Film coating examples were prepared on a 7 mil thickpoly(ethylene terephthalate) support and comprised a layer containingphenolic activating agent and the blocked compound (with contents shownbelow) with an overcoat layer of gelatin (0.22 g/m²) and1,1′-(methylenebis(sulfonyl))bis-ethene hardener (at 2% of the totalgelatin concentration). Both layers contained spreading aids tofacilitate coating. Component Laydown Blocked Developer 2.69 mMole/m²Activating Agent 0.86 g/m² Lime processed gelatin 4.3 g/m²

[0198] For comparison purposes, a comparative Blocked Developer (DC-1)represented by the following structure was tested:

[0199] The material was ball-milled in an aqueous mixture, for 4 daysusing Zirconia beads in the following formula. For 1 g of Incorporateddeveloper, sodium tri-isopropylnaphthalene sulfonate (0.1 g), water (to10 g), and beads (25 mL), were used. In some cases, after milling, theslurry was diluted with warmed (40° C.) gelatin solution (12.5%, 10 g)before the beads were removed by filtration. The filtrate (with orwithout gelatin addition) was stored in a refrigerator prior to use.

[0200] The incorporated developers (D-1, D-2, D-3, D-4) had thefollowing structures:

[0201] The above compounds were incorporated in the same way as forDC-1.

[0202] For comparison to the activating agents of the present invention,the comparative compounds were as follows:

[0203] Film Evaluation:

[0204] The different coatings were heated at specified temperatures for20 sec and a punch of each of the processed films was digested with 0.5mL aqueous Protease solution (1 mg/mL) at 40° C. and then treated with1.0 mL of tetrahydrofuran (THF) solvent (with 1% acetic acid). Themixture was filtered and analyzed with a reversed-phase high performanceliquid chromatography (HPLC), e.g., a Hewlett-Packard 1100 IPLC system.The amount of blocked compound recovered after the processing treatmentis reported as percentage of that found in the unprocessed film, whichis used as a reference, as shown below. Percent Blocked DeveloperRecovered (20 sec) Developer Activ. 130° C. 140° C. 150° C. 160° C. DC-1None NR 86.8% 85.4% 83.4% DC-1 A-1 94.8% 85.7% 83.7% 56.5% D-2 None NR93.3% 89.4% 88.1% D-2 A-1 58.8% 34.1% 9.2% 0.1% D-3 none 89.3% NR NR NRD-4 none NR NR NR NR

[0205] No reaction detected (NR) was assigned for experiments in which95% or more of the blocked developer remained. It is seen from thetabulated results that A-1 has a profound effect on the thermolysis ofD-2, whereas its effect on the comparative DC-1 is relatively small.Also the inventive blocked compounds D-3 and D-4 are essentially likeD-2 which is non-reactive without the melt-former A-1.

EXAMPLE 2

[0206] In this example the effect of the activating agent is evaluated.A-3 is incorporated into the coating melt as an aqueous solution withthe same laydown as the solid particle A-1. After processing andanalysis the following is obtained, which shows that with the inventiveblocked compounds only the phenolic activating agent A-1 has asignificant effect on their thermolyses. Percent of Blocked Dev.Recovered After 20 sec Dev. Activ. 130° C. 140° C. 150° C. 160° C. DC-1AC-3 88.5% 83.7% 83.1% 62.9% D-1 AC-3 NR NR NR 85.3% D-1 A-1 61.0% 34.8%13.1% 0.1% D-2 AC-3 NR NR 89.4% 84.9% D-4 AC-3 92.9% 94.1% 93.9% 92.0%

EXAMPLE 3

[0207] This example compares a soluble phenolic activator (A-18) with asolid particle non-phenolic compound (AC-4). After the same processingand analysis as in Example 1, the following table is obtained whichindicates that the phenolic activator A-18 is more active than thecomparative compound when present with the inventive blocked compounds.Percent of Blocked Dev. Recovered After 20 s Dev. Activ. 130° C. 140° C.150° C. 160° C. DC-1 AC-4 90.5% 92.6% 87.7% 79.2% DC-1 A-18 71.6% 58.9%37.4% 64.0% D-1 AC-4 NR 93.3% 90.3% 87.3% D-1 A-18 74.8% 56.4% 33.3%36.0% D-2 AC-4 91.2% 91.5% 84.7% 76.6% D-2 AF-18 71.6% 50.4% 31.1% 14.0%

EXAMPLE 4

[0208] In this example structures similar to A-1 were used. The coatingswere prepared like in example 1 except equimolar amounts of A-2, A-3,A-4, and A-5 were added in place of A-1. Same treatment and analysis ofthese coatings gave results listed in the following table. Again, thethermolysis of D-2 in the film environment is strongly facilitated bythe presence of these phenolic compounds as can be clearly seen in thetable. Percent of Blocked Dev. Recovered After 20 s Dev. Activ. 130° C.140° C. 150° C. 160° C. D-2 A-1 50.3% 32.0% 14.2% 0.0% D-2 A-2 87.2%44.3% 13.0% 3.5% D-2 A-5 NR 94.5% 30.9% 6.5% D-2 A-3 70.2% 42.6% 17.1%3.1% D-2 A-4 94.6% 61.8% 14.2% 4.6%

[0209] Although the invention has been illustrated with these specificexamples involving developers, it is clearly applicable to the thermalrelease of other types of photographically useful groups.

EXAMPLE 5

[0210] The following further demonstrate the interaction between thephenolic melt-formers and the blocked compounds in a solutionenvironment. In these experiments, an activating agent was dissolved at0.010 M (10 mM) in anhydrous dimethylsulfoxide (DMSO) solvent that hadbeen heated to 130° C. The blocked compound, D-1 (in DMSO, 0.2 M), wasthen added so that in the reaction mixture its concentration was 0.0001M. The reaction mixture was analyzed at various time intervals with aHPLC system (HEWLETT-PACKARD 1100). The rate constant (k) of decay ofD-1 under the conditions was obtained by plotting the logarithm of itsHPLC area vs. time. The half-lives (t_(½)) were calculated as:$t_{1/2} = \frac{\ln \quad 2}{k}$

[0211] The results are listed in the following table. It is obvious thatthe potential activating agent with a phenolic group enhance thereaction of D-1 while the comparative compound AC-2 shows no significanteffect. Half-life of D-1 in DMSO (130° C.): Containing Activ. (10 mM)t_(½), min A-1 62.4 A-2 57.3 A-3 72.2 A-4 83.5 A-5 75.3 A-8 29.0  A-1929.4 A-9 133.3 A-7 277.3  A-10 83.5  A-16 14.6 A-6 27.5 None >1000 AC-2938.2

[0212] The invention has been described in detail with particularreference to preferred embodiments, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

What is claimed is:
 1. An imaging element comprising an imaging layerhaving associated therewith a blocked color-forrning agent inassociation with a phenolic activating agent, wherein the blocked colorforming agent is represented by Structure I:

wherein PUG is a photographically useful group that is a color-formingagent; TIME is a timing group; T represents t independently selectedsubstituted or unsubstituted alkyl or aryl groups, t is 0, 1, or 2 andif t is 2, the T groups can form a ring; HET is a heterocyclic groupwhich optionally can form a ring with a T group; R₁₂ is hydrogen,substituted or unsubstituted alkyl or substituted or unsubstituted aryl,or R₁₂ can form a ring with a T group or with HET; l is 0 or 1; m is 0,1, or 2; and n is 0 or 1; where LINK 1 and LINK 2 are independently ofStructure II:

wherein X represents carbon or sulfur; Y represents oxygen, sulfur orN—R₁, where R₁ is substituted or unsubstituted alkyl or substituted orunsubstituted aryl; p is 1 or2; Z represents carbon, oxygen or sulfur; ris 0 or 1; with the proviso that when X is carbon, both p and r are 1,when X is sulfur, Y is oxygen, p is 2 and r is 0; # denotes the bond toPUG (for LINK 1) or TIME (for LINK 2): $ denotes the bond to TIME (forLINK 1) or T_((t)) substituted carbon (for LINK 2); wherein the phenolicactivating agent for unblocking the color-forming agent of Structure Iis represented by the following Structure IV: Ar—(OH)_(q)   (IV) whereinq≧1 and Ar is a substituted or unsubstituted aromatic group.
 2. Animaging element according to claim 1, wherein PUG is a coupler,development inhibitor, inhibitor releasing developer, dye or dyeprecursor, developing agent, or precursors thereof.
 3. An imagingelement according to claim 2, wherein PUG is a developer.
 4. An imagingelement according to claim 3, wherein the developer is an aminophenol,phenylenediarnine, hydroquinone, pyrazolidinone, or hydrazine.
 5. Animaging element according to claim 4, wherein the developer is aphenylenediamine.
 6. An imaging element according to claim 1, where LINK1 and LNK 2 are the following:


7. An imaging element according to claim 7, wherein LINK 1 is


8. An imaging element according to claim 1, wherein TIME is a timinggroup selected from (1) groups utilizing an aromatic nucleophilicsubstitution reaction; (2) groups utilizing the cleavage reaction of ahemiacetal; (3) groups utilizing an electron transfer reaction along aconjugated system; or (4) groups using an intramolecular nucleophilicsubstitution reaction.
 9. An imaging element according to claim 1,wherein HET is selected from substituted or unsubstitutedbenzimidazolyl, benzothiazolyl, benzoxazolyl, benzothiophenyl,benzofuryl, furyl, imidazolyl, indazolyl, indolyl, isoquinolyl,isothiazolyl, isoxazolyl, oxazolyl, picolinyl, purinyl, pyranyl,pryazinyl, pyrazolyl, pyridyl, pyrimidinyl, pyrrolyl, quinaldinyl,quinazolinyl, quinolyl, quinoxalinyl, tetrazolyl, thiadiazolyl,thiatriazolyl, thiazolyl, thiophenyl, and triazolyl group.
 10. Animaging element according to claim 9, wherein HET comprises asubstituted or unsubstituted 2-imidazolyl, 2-benzimidazolyl,2-thiazolyl, 2-benzothiazolyl, 2-oxazolyl, 2-benzoxazolyl, 2-pyrydyl,2-quinolinyl, 1-isoquinolinyl, 2-pyrrolyl, 2-indolyl, 2-thiophenyl,2-benzothiophpenyl, 2-furyl, 2-benzofuryl, 2-,4-, or 5-pyrimidinyl,2-pyrazinyl, 3-,4-, or 5-pyrazolyl, 3-indazolyl, 2-(1,3,4-triazolyl),4-or 5-(1,2,3-triazolyl), 5-(1,2,3,4-tetrazolyl) group.
 11. An imagingelement according to claim 1, wherein the compound of Structure I is ofStructure III:

wherein: HET is a heterocyclic group; W is OH or NR₂R₃, and R₂ and R₃are independently hydrogen or a substituted or unsubstituted alkyl groupor R₂ and R₃ are connected to form a ring; R₅, R₆, R₇, and R₈ areindependently hydrogen, halogen, hydroxy, amino, alkoxy, carbonamido,sulfonamido, alkylsulfonamido or alkyl, or R₅ can connect with R₃ or R₆and/or R₈ can connect to R₄ or R₇ to form a ring; R₉, R₁₀ and R₁₁ areindependently hydrogen, alkyl, aryl, heteroaromatic or alkoxy groups, orany two of R₉, R₁₀, R₁₁ and HET can be connected to form a ring.
 12. Animaging element according to claim 11, wherein HET comprises asubstituted or unsubstituted benzimidazolyl, benzothiazolyl,benzoxazolyl, benzothiophenyl, benzofuryl, furyl, imidazolyl, indazolyl,indolyl, isoquinolyl, isothiazolyl, isoxazolyl, oxazolyl, picolinyl,purinyl, pyranyl, pyrazinyl, pyrazolyl, pyridyl, pyrimidinyl, pyrrolyl,quinaldinyl, quinazolinyl, quinolyl, quinoxalinyl, tetrazolyl,thiadiazolyl, thiatriazolyl, thiazolyl, thiophenyl, or triazolyl group.13. An imaging element according to claim 12, wherein HET is a2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-benzothiazolyl,2-oxazolyl, 2-benzoxazolyl, 2-pyridyl, 2-quinolinyl, 1-isoquinolinyl,2-pyrrolyl, 2-indolyl, 2-thiophenyl, 2-benzothiophenyl, 2-furyl,2-benzofuryl, 2-,4-, or 5-pyrimidinyl, 2-pyrazinyl, 3-,4-, or5-pyrazolyl, 3-indazolyl, 2-(1,3,4-triazolyl), 4-or 5-(1,2,3-triazolyl),or 5-(1,2,3,4-tetrazolyl) group.
 14. An imaging element according toclaim 1 wherein the phenolic activating agent has the followingstructure:

wherein LINK is selected from the group consisting of —C(═O)NH—,—NHC(═O)—, —NHSO₂—, —C(═O)—, —O—, —C(═O)O—, —SO₂NH—, and —SO₂—; whereinthe substituent R is independently selected from a substituted orunsubstituted alkyl, ether, cycloalkyl, aryl, alkylaryl, hydroxy,carboxylic acid, nitro, halogen, heteroaromatic, or wherein two Rsubstituents form an aromatic or aliphatic or unsaturated ring; p is 0to4;n is 0 to 4; and wherein p+n is 1 to
 5. 15. An imaging elementaccording to claim 1 wherein the phenolic activating agent has thefollowing structure:

wherein B is selected from the group consisting of —C(═O)NHR³,—NHC(═O)R³, —NHSO₂R³ , —C(═O)R³, —C(═O)OR³, —OR³, —SO₂NHR³, and —SO₂R³;where R³ is hydrogen or substituted or unsubstituted alkyl group; and mis 0 to 4; wherein the substituent R is independently selected from asubstituted or unsubstituted alkyl, ether, cycloalkyl, aryl, alkylaryl,hydroxy, carboxylic acid, nitro, halogen, heteroaromatic, or wherein twoR substituents form an aromatic or aliphatic or unsaturated ring; n is 0to 4; and, wherein m+n is 1 to
 5. 16. An imaging element according toclaim 14 wherein R is independently selected from substituted orunsubstituted C₁ to C₁₀ alkyl group.
 17. The color photothermographicelement of claim 1 in which the phenolic compound is present in theamount of 0.01 times to 0.5 times the amount by weight of coated gelatinper square meter.
 18. An imaging element according to claim 1, whereinthe compound of Structure I and IV are in the imaging layer.
 19. Animaging element according to claim 1 which is a photothermographicelement.
 20. An imaging element according to claim 19, wherein thephotothermographic element contains an imaging layer comprising a lightsensitive silver halide emulsion, a non-light sensitive silver saltoxidizing agent and a reducing agent.
 21. An imaging element accordingto claim 1, which is a photographic element.
 22. An imaging elementaccording to claim 21, wherein the photographic element contains animaging layer comprising a light sensitive silver halide emulsion. 23.An imaging element according to claim 1, wherein the imaging element isa thermographic imaging element.
 24. An imaging element according toclaim 23, wherein the thermographic imaging element contains an imaginglayer comprising a non-light sensitive silver salt oxidizing agent and areducing agent.
 25. An imaging element according to claim 23, whereinthe thermographic imaging element contains an imaging layer comprising areleasable dye or dye precursor and a phenolic activating agent.
 26. Amethod of image formation comprising the step of developing an imagewiseexposed imaging element according to claim
 1. 27. A method according toclaim 26, wherein said developing comprises treating said imagewiseexposed element at a temperature between about 90° C. and about 180° C.for a time ranging from about 0.5 to about 60 seconds.
 28. A methodaccording to claim 26, wherein said developing comprises treating saidimagewise exposed element to a volume of processing solution is betweenabout 0.1 and about 10 times the volume of solution required to fullyswell the photographic element.
 29. A method according to claim 28,wherein the developing is accompanied by the application of a laminatesheet containing additional processing chemicals
 30. A method accordingto claim 28, wherein the developing is conducted at a processingtemperature between about 20° C. and about 100° C.
 31. A methodaccording to claim 28, wherein the applied processing solution is abase, acid, or pure water.
 32. A method according to claim 26, whereinsaid developing comprises treating said imagewise element with aconventional photographic processing solution.
 33. A method of imageformation comprising the step of scanning and imagewise exposed anddeveloped imaging element according to claim 1 to form a firstelectronic image representation of said imagewise exposure.